Favorable Outcome Probability - ISEE Lower Level Mathematics Achievement

What is the probability of choosing a blue marble from $5$ red and $3$ blue marbles?

$\frac{3}{8}$ . With 3 blue marbles out of a total of 8, the ratio determines the probability of selecting blue.
What is the probability of choosing a prime number from the integers $1$ through $10$ ?

$\frac{2}{5}$ . Prime numbers between 1 and 10 (2, 3, 5, 7) are four out of ten integers.
What is the probability of getting exactly one head in two fair coin flips?

$\frac{1}{2}$ . The sample space has four outcomes (HH, HT, TH, TT), with exactly one head occurring in two of them (HT, TH).
What is the probability of choosing a consonant from the letters in the word MATH?

$\frac{3}{4}$ . The word MATH has four letters, with three consonants (M, T, H).
What is the probability of choosing a multiple of $3$ from the integers $1$ through $9$ ?

$\frac{1}{3}$ . From 1 to 9, the multiples of 3 (3, 6, 9) are three out of nine integers.
What is the probability of choosing a heart from a standard $52$ -card deck?

$\frac{1}{4}$ . A standard deck has 13 hearts out of 52 cards, assuming equal likelihood.
What is the probability of choosing a vowel from the letters in the word MATH?

$\frac{1}{4}$ . The word MATH has four letters, with one vowel (A) among them.
What is the probability of choosing a number less than $5$ from the integers $1$ through $10$ ?

$\frac{2}{5}$ . Numbers less than 5 (1, 2, 3, 4) are four out of ten integers from 1 to 10.
What is the probability of choosing a face card from a standard $52$ -card deck?

$\frac{3}{13}$ . There are 12 face cards (J, Q, K in 4 suits) out of 52 cards in a standard deck.
What is the probability of rolling a number greater than $4$ on a fair $6$ -sided number cube?

$\frac{1}{3}$ . Numbers greater than 4 (5, 6) are two out of six possible outcomes on a fair cube.
What is the probability of rolling an even number on a fair $6$ -sided number cube?

$\frac{1}{2}$ . Even numbers (2, 4, 6) are three out of six possible outcomes on a fair cube.
What is the probability of choosing a black card from a standard $52$ -card deck?

$\frac{1}{2}$ . Half of the 52 cards in a standard deck are black (spades and clubs).
What is the probability of choosing a number greater than $3$ on a fair spinner labeled $1$ to $8$ ?

$\frac{5}{8}$ . Numbers greater than 3 (4 through 8) are five out of eight possible outcomes on the spinner.
What is the probability of choosing a month with $31$ days from the $12$ months of the year?

$\frac{7}{12}$ . Seven months (January, March, May, July, August, October, December) have 31 days out of 12.
What is the probability of choosing a weekend day from the $7$ days of the week?

$\frac{2}{7}$ . Weekend days (Saturday, Sunday) are two out of seven days in a week.
What is the probability of an event that has $0$ favorable outcomes out of $n$ total outcomes?

$0$ . An event with no favorable outcomes is impossible, resulting in zero probability regardless of the total outcomes.
What is the probability of choosing an ace from a standard $52$ -card deck?

$\frac{1}{13}$ . A standard deck has 4 aces out of 52 cards.
What is the probability of choosing a factor of $12$ from the integers $1$ through $12$ ?

$\frac{1}{2}$ . Factors of 12 (1, 2, 3, 4, 6, 12) are six out of twelve integers from 1 to 12.
What is the probability of getting at least one head in two fair coin flips?

$\frac{3}{4}$ . Three out of four outcomes in two coin flips include at least one head (HH, HT, TH).
What is the formula for probability using favorable outcomes and total outcomes?

$P(\text{event})=\frac{\text{favorable outcomes}}{\text{total outcomes}}$ . This formula defines the probability of an event as the ratio of favorable outcomes to total possible outcomes in a sample space assuming equal likelihood.
What is the probability of rolling a $4$ on a fair $6$ -sided number cube?

$\frac{1}{6}$ . A fair 6-sided cube has one favorable outcome (4) out of six equally likely outcomes.
What is the probability of an event that has $n$ favorable outcomes out of $n$ total outcomes?

$1$ . When all outcomes are favorable, the event is certain, yielding a probability of one.
What is the probability of flipping heads on a fair coin?

$\frac{1}{2}$ . A fair coin has two equally likely outcomes, with heads being one of them.
What is the probability of choosing a red marble from $5$ red and $3$ blue marbles?

$\frac{5}{8}$ . With 5 red marbles out of a total of 8, the ratio gives the probability of selecting red.
What is the probability of getting two heads in two fair coin flips?

$\frac{1}{4}$ . Out of four possible outcomes in two coin flips, only one (HH) results in two heads.

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