Probability — SSAT Upper practice questions

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Practice 142 Probability questions in the app

What this topic is

Probability measures how likely an outcome is, written as favorable outcomes divided by the total number of equally likely outcomes.

SSAT Upper probability questions usually involve drawing items from a bag, choosing a person from a group, or picking numbers from a range. Many are easiest through the complement: the chance something does not happen is one minus the chance it does. A product of two whole numbers is odd only when both are odd, so counting the odd cases first gives the chance of an even product.

Answers appear as fractions, and a wrong choice often uses the wrong total, such as counting only one group instead of everyone.

Sample questions

Pick an answer to see whether it is right — nothing is saved, and nothing needs an account.

Question 1Easier

A bag contains 5 red counters and 4 white counters. If one counter is selected at random, what is the probability that the counter will not be red?

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Answer: B — $\frac{4}{9}$

There are 4 white counters and $5 + 4 = 9$ counters total. The probability of not red is $\frac{4}{9}$ .

Question 2Mid

Two different integers are selected at random from the integers 1 through 12. What is the probability that their product is even?

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Answer: D — $\frac{17}{22}$

The product is odd only if both selected integers are odd. There are 6 odd integers from 1 through 12, so the probability of selecting two odd integers is $\frac{6}{12} \cdot \frac{5}{11} = \frac{5}{22}$ . Therefore, the probability that the product is even is $1 - \frac{5}{22} = \frac{17}{22}$ .

Question 3Mid

At a workshop, each person chose exactly one of four activities: 18 people chose Drawing, 12 chose Strategy games, 15 chose Robotics, and 9 chose Music. If one person is selected at random, what is the probability that the person chose Drawing or Robotics?

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Answer: C — $\frac{11}{18}$

Drawing or Robotics accounts for $18 + 15 = 33$ people. The total is $18 + 12 + 15 + 9 = 54$ , and $33 / 54 = 11 / 18$ .

Every question is picked for where you are right now, wrong answers come back until they stick, and it all works offline.

Practice 142 Probability questions in the app

Probability — SSAT Upper practice questions

What this topic is

Sample questions

More SSAT Upper topics

Quantitative (Math)