How to find the probability of an outcome - ISEE Lower Level Quantitative Reasoning
Card 0 of 695
Eric has a 2 red shirts, 3 orange shirts, 4 purple shirts, and 1 pink shirt. If Eric randomly chooses a shirt, what are the chances that he selects a pink shirt?
Eric has a 2 red shirts, 3 orange shirts, 4 purple shirts, and 1 pink shirt. If Eric randomly chooses a shirt, what are the chances that he selects a pink shirt?
First, add up all of the shirts.
We then see that Eric has 1 pink shirt and 10 shirts from which to choose. Build a fraction with the number of pink shirts on top, and the total number of shirts on the bottom, 
.
First, add up all of the shirts.
We then see that Eric has 1 pink shirt and 10 shirts from which to choose. Build a fraction with the number of pink shirts on top, and the total number of shirts on the bottom,
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Ten cards each have a number printed on them. Five have a 1 printed on them, three have a 2, and two have a 3. The cards are shuffled and a card is dealt. What is the probability that the card will not be a 3?
Ten cards each have a number printed on them. Five have a 1 printed on them, three have a 2, and two have a 3. The cards are shuffled and a card is dealt. What is the probability that the card will not be a 3?
There are ten cards total, and eight cards that are not threes. This makes the probability of drawing a three
There are ten cards total, and eight cards that are not threes. This makes the probability of drawing a three
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Express the probability as a fraction.
Nija has 7 marbles. There are 2 red, 3 blue, and 2 yellow. What is the probablilty that Nija will choose a red marble?
Express the probability as a fraction.
Nija has 7 marbles. There are 2 red, 3 blue, and 2 yellow. What is the probablilty that Nija will choose a red marble?
Probability can be expressed as a fraction:
Our fraction is 
.
Since there are 2 red marbles out of 7 total marbles, the probability of choosing a red marble is 
.
Probability can be expressed as a fraction:
Our fraction is
Since there are 2 red marbles out of 7 total marbles, the probability of choosing a red marble is
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A ring toss game has 25 bottles, 5 of which are yellow. If you toss a ring around a yellow bottle, you win the grand prize. What is the probability of winning the grand prize? (Give the fraction in simplest form.)
A ring toss game has 25 bottles, 5 of which are yellow. If you toss a ring around a yellow bottle, you win the grand prize. What is the probability of winning the grand prize? (Give the fraction in simplest form.)
To find the probability of an outcome, set up a fraction.
Since there are 5 yellow (part) out of 25 bottles (total possible) the fraction looks like this: 
.
Reduce the fraction by dividing the top and bottom by 5:
This is the probability of winning the grand prize.
To find the probability of an outcome, set up a fraction.
Since there are 5 yellow (part) out of 25 bottles (total possible) the fraction looks like this:
Reduce the fraction by dividing the top and bottom by 5:
This is the probability of winning the grand prize.
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A magician holds in his bag 3 green balls, 4 red balls and 7 blue balls. What is the probability of drawing a red ball from the bag?
A magician holds in his bag 3 green balls, 4 red balls and 7 blue balls. What is the probability of drawing a red ball from the bag?
Probability = total number of possible outcomes/sample space.
= 
= 
Probability = total number of possible outcomes/sample space.
=
=
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If there are 2 blue marbles and 18 red marbles in a jar, what is the probability that Jeff will pick out a red marble?
If there are 2 blue marbles and 18 red marbles in a jar, what is the probability that Jeff will pick out a red marble?
First, add the total number of marbles, which is 
. There are 18 red marbles, so you set up a fraction 
.
If you simplify by dividing the numerator and denominator by 2, you get 
.
First, add the total number of marbles, which is
If you simplify by dividing the numerator and denominator by 2, you get
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In a restaurant there are two managers, three workers, and twelve guests. What is the probability that a person chosen at random is a worker?
In a restaurant there are two managers, three workers, and twelve guests. What is the probability that a person chosen at random is a worker?
The total number of people in the room is the sum of all the different types of people:
The probability of choosing a worker is the number of workers divided by the total number of people. There are three workers and seventeen people in total:
The total number of people in the room is the sum of all the different types of people:
The probability of choosing a worker is the number of workers divided by the total number of people. There are three workers and seventeen people in total:
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Find the probability of an outcome. Express the outcome as fraction, reduced to its lowest terms.
Mr. Thomas went to a car lot to buy a new car. Of the 68 cars on the lot, 22 were black, 16 were silver, 8 were white, 12 were blue, and 10 were red. What is the probability that Mr. Thomas will buy a blue car?
Find the probability of an outcome. Express the outcome as fraction, reduced to its lowest terms.
Mr. Thomas went to a car lot to buy a new car. Of the 68 cars on the lot, 22 were black, 16 were silver, 8 were white, 12 were blue, and 10 were red. What is the probability that Mr. Thomas will buy a blue car?
To find the probability of an outcome, set up a fraction:
Since there are 12 blue cars (part) out of 68 cars in all (total possible) the fraction looks like this:
If you reduce the fraction by 4 (because the numerator and the denominator are both divisible by 4 which makes 4 the GCF (greatest common factor), it becomes:
To find the probability of an outcome, set up a fraction:
Since there are 12 blue cars (part) out of 68 cars in all (total possible) the fraction looks like this:
If you reduce the fraction by 4 (because the numerator and the denominator are both divisible by 4 which makes 4 the GCF (greatest common factor), it becomes:
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There are 10 marbles in a bag:
7 red
2 blue
1 yellow
What is the probability of choosing a red ball out of the bag?
There are 10 marbles in a bag:
7 red
2 blue
1 yellow
What is the probability of choosing a red ball out of the bag?
To find the probability of an outcome, set up a fraction:
Since there are 7 red marbles (part) out of 10 marbles in all (total possible) the fraction looks like this:
To find the probability of an outcome, set up a fraction:
Since there are 7 red marbles (part) out of 10 marbles in all (total possible) the fraction looks like this:
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Casey has a bag containing red, yellow, blue, and green beads. There are equal numbers of red and blue beads, which comprise half the bag when combined. If there are 24 beads in the bag, what is the probability that Casey will select a blue bead?
Casey has a bag containing red, yellow, blue, and green beads. There are equal numbers of red and blue beads, which comprise half the bag when combined. If there are 24 beads in the bag, what is the probability that Casey will select a blue bead?
There are 
beads in Casey's bag. We know that the red and blue beads make up half of the bag, so we divide 
by 
to find the total number of red and blue beads.
Since there is an equal number of red and blue beads, we divide 
by 
.
To find probability, we create a fraction with our desired outcome written as the numerator and the total possible outcomes written as the denominator:
Since 
and 
are divisible by 
, we must reduce the fraction.
There are
Since there is an equal number of red and blue beads, we divide
To find probability, we create a fraction with our desired outcome written as the numerator and the total possible outcomes written as the denominator:
Since
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A bag contains 
red socks and 
purple socks. What is the chance that I pick a purple sock from the bag?
A bag contains
To find the probability of picking a purple sock from the bag of socks, we need to set up a fraction like this: 
. The problem tells us that we have 
purple socks, so we can put that on the top of the fraction. The total number of socks is equal to 
purple socks + 
red socks, giving us a sum of 
(which goes on the bottom of the fraction). That gives us a 
chance of picking a purple sock from the bag!
To find the probability of picking a purple sock from the bag of socks, we need to set up a fraction like this:
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Mikey has a box filled with cookies. He has 6 chocolate chip cookies, 4 sugar cookies, and 2 oatmeal raisin cookies. What is the chance that Mikey picks a sugar cookie out of the box?
Mikey has a box filled with cookies. He has 6 chocolate chip cookies, 4 sugar cookies, and 2 oatmeal raisin cookies. What is the chance that Mikey picks a sugar cookie out of the box?
To find the probability of picking a sugar cookie from the bag of cookies, we need to set up a fraction like this:
The problem tells us that Mikey has 4 sugar cookies, so we can put that on the top of the fraction. The total number of cookies is equal to 6 chocolate chip cookies + 4 sugar cookies + 2 oatmeal raisin cookies, giving us a sum of 12 (which goes on the bottom of the fraction). That gives Mikey a 
chance of picking a sugar cookie!
To find the probability of picking a sugar cookie from the bag of cookies, we need to set up a fraction like this:
The problem tells us that Mikey has 4 sugar cookies, so we can put that on the top of the fraction. The total number of cookies is equal to 6 chocolate chip cookies + 4 sugar cookies + 2 oatmeal raisin cookies, giving us a sum of 12 (which goes on the bottom of the fraction). That gives Mikey a
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Sofia has a pizza pie with 8 slices. 4 slices have pepperoni, 3 slices have mushrooms and 1 slice has olives. If Sofia randomly picks a piece of pizza to eat, what is the chance that the slice of pizza has mushrooms on it?
Sofia has a pizza pie with 8 slices. 4 slices have pepperoni, 3 slices have mushrooms and 1 slice has olives. If Sofia randomly picks a piece of pizza to eat, what is the chance that the slice of pizza has mushrooms on it?
To find the probability of picking a mushroom slice from the pizza pie, we should set up a fraction like this:
The problem tells us that we have 3 mushroom slices, so we can put that on the top of the fraction. The problem also tells us that we have 8 total slices in the pizza pie, so that can go on the bottom of the fraction. That gives Sofia a 
chance of picking a mushroom slice!
To find the probability of picking a mushroom slice from the pizza pie, we should set up a fraction like this:
The problem tells us that we have 3 mushroom slices, so we can put that on the top of the fraction. The problem also tells us that we have 8 total slices in the pizza pie, so that can go on the bottom of the fraction. That gives Sofia a
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Jenny buys two dozen donuts from the bakery. If 12 donuts are glazed, 6 donuts are jelly, 4 donuts are powdered and 2 donuts are plain, what is the chance that she will randomly pick a powdered donut from the box?
Jenny buys two dozen donuts from the bakery. If 12 donuts are glazed, 6 donuts are jelly, 4 donuts are powdered and 2 donuts are plain, what is the chance that she will randomly pick a powdered donut from the box?
To find the probability of picking a powdered donut from the box of donuts, we need to set up a fraction like this:
. The problem tells us that we have 4 powdered donuts, so we can put that on the top of the fraction. The total number of donuts is 2 dozen, which is equal to 24 donuts (which goes on the bottom of the fraction). That gives Jenny a 
chance of picking a powdered donut from the box!
To find the probability of picking a powdered donut from the box of donuts, we need to set up a fraction like this:
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Caroline has 3 books, 2 pencils, 1 candy, and 4 binders in her backpack. If she randomly chooses an item from her backpack, what is the probability of her randomly picking out a pencil?
Caroline has 3 books, 2 pencils, 1 candy, and 4 binders in her backpack. If she randomly chooses an item from her backpack, what is the probability of her randomly picking out a pencil?
Probability is all about part and whole. First, add up how many items are in her backpack (10). Then, notice how many pencils she has (2). Put the part over the whole, which gives you 
.
This can be further simplified/reduced to 
.
Probability is all about part and whole. First, add up how many items are in her backpack (10). Then, notice how many pencils she has (2). Put the part over the whole, which gives you
This can be further simplified/reduced to
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Joey has 10 shirts on his bed. 4 shirts are blue, 3 shirts are purple, 2 shirts are green, and 1 shirt is white. What is the chance that Joey randomly picks a purple shirt from the shirts on his bed?
Joey has 10 shirts on his bed. 4 shirts are blue, 3 shirts are purple, 2 shirts are green, and 1 shirt is white. What is the chance that Joey randomly picks a purple shirt from the shirts on his bed?
To find the probability of picking a purple shirt from the pile of shirts on Joey's bed, we need to set up a fraction like this:
The problem tells us that Joey has 3 purple shirts, so we can put that in the numerator. We are also told that the total number of shirts on Joey's bed is 10, so 10 goes on the bottom of the fraction. Therefore, Joey has a 
chance of picking a purple shirt.
To find the probability of picking a purple shirt from the pile of shirts on Joey's bed, we need to set up a fraction like this:
The problem tells us that Joey has 3 purple shirts, so we can put that in the numerator. We are also told that the total number of shirts on Joey's bed is 10, so 10 goes on the bottom of the fraction. Therefore, Joey has a
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A bag of marbles contains 
green marbles, 
blue marbles, and 
red marbles.
If 
marbles are taken from the bag on each draw, what is the greatest possible amount of draws that can occur without drawing a red marble?
A bag of marbles contains
If
There are 
green marbles and 
red marbles in the bag. Adding these amounts together gives 
marbles in the bag that are not red. If all 
of these were drawn before any red marble, this would require 
draws at 
marbles per draw (
). Therefore, it is possible to draw up to 
times without drawing a red marble.
There are
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Sarah, Mitch, and Ben are going to a concert. If they are seated in a row of 
, what fraction represents the probability Sarah will be seated in the middle of the row?
Sarah, Mitch, and Ben are going to a concert. If they are seated in a row of
The number of total possible arrangements of three items in a row is 
, or 
.
We can write out all the possible arrangments and count the number in which Sarah sits in the middle.
-
-
-
-
-
-
In 
out of 
possible arrangements, Sarah sits in the middle. Expressed as a fraction, this is 
, which is equivalent to 
.
The number of total possible arrangements of three items in a row is
We can write out all the possible arrangments and count the number in which Sarah sits in the middle.
In
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Shannon has a box with 9 shirts inside. 4 shirts are pink, 3 shirts are yellow, 1 shirt is red, and 1 shirt is green. What is the probability that Shannon will randomly pick a pink shirt from the box?
Shannon has a box with 9 shirts inside. 4 shirts are pink, 3 shirts are yellow, 1 shirt is red, and 1 shirt is green. What is the probability that Shannon will randomly pick a pink shirt from the box?
To find the probability of picking a pink shirt from the box, we need to set up a fraction: 
. The problem tells us that Shannon has 4 pink shirts, so we can put that on the top of the fraction. The total number of shirts is 9, which goes on the bottom of the fraction. That gives Shannon a 
chance of picking a pink shirt from the box!
To find the probability of picking a pink shirt from the box, we need to set up a fraction:
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Tucker is going fishing at a local pond with 15 fish. 5 fish are tuna, 4 fish are salmon, 3 fish are yellowtail, and 3 fish are trout. What is the chance that the first fish Tucker catches will be a tuna or a trout?
Tucker is going fishing at a local pond with 15 fish. 5 fish are tuna, 4 fish are salmon, 3 fish are yellowtail, and 3 fish are trout. What is the chance that the first fish Tucker catches will be a tuna or a trout?
To find the probability of Tucker catching a tuna or a trout, we need to set up a fraction like this: 
. The problem tells us that there are 5 tuna and 3 trout in the pond, so we can put 8 on the top of the fraction. The total number of fish in the pond is 15, so that goes on the bottom of the fraction. That gives Tucker an 8/15 chance of catching a tuna or trout!
To find the probability of Tucker catching a tuna or a trout, we need to set up a fraction like this:
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