Arithmetic

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ACT Math › Arithmetic

Questions 1 - 10
1

What common number can you add to the numerator and denominator of to get ?

Explanation

Set up an equation where you add the same unknown number (x) to both the numerator and the denominator of the original fraction, and set the equation equal to .

Cross-multiply the fractions to simplify.

Now, solve for x.

2

A car averages 29 miles per gallon. If gas costs $3.75 per gallon how much money would need to be spent on gas to travel 1464.5 miles?

$189.38

$5491.88

$108.75

$50.5

None of the other answers

Explanation

The question is asking for the amount of money that would need to be spent on gas. Using the value given for the miles per gallon of the car and the amount of miles traveled it is possible to determine the gallons of fuel that will be required. This will be set up as 1464.5 miles travelled divided by the 29 miles per gallon that the car gets. This leaves us with 50.5 gallons of fuel used. From this point we can multiply the amount of fuel used, 50.5 gallons, by the price of fuel per gallon, $3.75, to obtain the amount of money that will spent on fuel, $189.38.

3

A car averages 29 miles per gallon. If gas costs $3.75 per gallon how much money would need to be spent on gas to travel 1464.5 miles?

$189.38

$5491.88

$108.75

$50.5

None of the other answers

Explanation

The question is asking for the amount of money that would need to be spent on gas. Using the value given for the miles per gallon of the car and the amount of miles traveled it is possible to determine the gallons of fuel that will be required. This will be set up as 1464.5 miles travelled divided by the 29 miles per gallon that the car gets. This leaves us with 50.5 gallons of fuel used. From this point we can multiply the amount of fuel used, 50.5 gallons, by the price of fuel per gallon, $3.75, to obtain the amount of money that will spent on fuel, $189.38.

4

To find the sale price for a single item or group of like items, one can use the equation , where is the discounted price, is the original price, and is the percent to be discounted in decimal form.

A pair of headphones normally sells for . If the headphones are on a -off discount, how expensive are they?

Explanation

To find the new sale price, apply the discount to the original price in decimal form.

--->

5

A bowl contains marbles that are either red or green. The probability of selecting a red marble at random from the bowl is

Which of the following expressions represents the total number of red marbles in the bowl?

Explanation

It’s best to start with a fraction that is a part over 100. For this problem, we are looking for a fraction that shows . If you go through the choices available, . Therefore, if you plug in any value for “X” in this fraction, you will know the total number of marbles in the bowl. Here is an example:

If there are 4 marbles in the bowl, you’d expect 1 to be red. If we use this equation, we get

6

At the beginning of a race, a person's speed is miles per hour. One hour into the race, a person increases his speed by . A half an hour later, he increases again by another . If he finishes this race in two hours, what is the average speed for the entire race? Round to the nearest hundredth of a mile per hour.

Explanation

Recall that in general

Now, let's gather our three rates:

Rate 1:

Rate 2:

Rate 3:

Now, we know that the time is a total of hours. Based on our data, we can write:

This is miles per hour, which rounds to .

7

Solve:

Explanation

This problem can be solved using common factors.

Rewrite using factors.

8

Solve:

Explanation

This problem can be solved using common factors.

Rewrite using factors.

9

Maria owns an art studio and spent in supplies. She sells her paintings for each. How many paintings does Maria need to sell until she makes a profit?

Explanation

Divide the total money spent by the cost of each painting.

Therefore, to make a profit, she needs to sell more than this amount. Since she can't sell a portion of a painting, the answer has to be the next nearest whole number ().

10

The number 9 is the second smallest integer with 3 factors, 1, 3, and 9. What is the sum of the factors of the smallest integer with only 3 factors?

4

7

13

15

17

Explanation

Here we must do two things. First we must find the smallest integer with 3 factors, then we must add those factors so that we can obtain our answer.

Looking at numbers less than 9 with only 3 factors, the only possibility is the number 4, whose factors are 1, 2, and 4.

The sum of these factors is 1 + 2 + 4 = 7

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