SSAT Upper Level Quantitative Quiz: Calculating The Mean
4 questions · exam conditions
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Calculating The MeanQuestion 1 of 4

A company tracks the number of hours worked per week by its employees. For 12 employees, the mean is 38 hours. For another group of 8 employees, the mean is 44 hours. What is the overall mean number of hours worked per week for all 20 employees?

40.4 hours
41.0 hours
42.2 hours
39.8 hours
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SSAT Upper Level Quantitative Quiz

SSAT Upper Level Quantitative Quiz: Calculating The Mean

Practice Calculating The Mean in SSAT Upper Level Quantitative with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Calculating The Mean, giving you a quick way to practice the rules, question types, and explanations that matter most for SSAT Upper Level Quantitative.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

A company tracks the number of hours worked per week by its employees. For 12 employees, the mean is 38 hours. For another group of 8 employees, the mean is 44 hours. What is the overall mean number of hours worked per week for all 20 employees?

  1. 40.4 hours (correct answer)
  2. 41.0 hours
  3. 42.2 hours
  4. 39.8 hours
Explanation: To find the weighted mean, calculate the total hours for each group and combine them. Group 1: 12 × 38 = 456 hours. Group 2: 8 × 44 = 352 hours. Total hours = 456 + 352 = 808 hours for 20 employees. Overall mean = 808 ÷ 20 = 40.4 hours. Choice B incorrectly averages 38 and 44 without considering group sizes. Choice C weights the groups incorrectly, favoring the smaller group. Choice D makes an arithmetic error in the final division.

Question 2

The mean of 8 numbers is 15. If two numbers, 12 and 18, are removed from the set, what is the mean of the remaining 6 numbers?

  1. 15.0 (correct answer)
  2. 14.5
  3. 15.5
  4. 16.0
Explanation: The sum of the original 8 numbers is 8 × 15 = 120. After removing 12 and 18, the sum of the remaining 6 numbers is 120 - 12 - 18 = 90. The new mean is 90 ÷ 6 = 15.0. Choice B incorrectly assumes the removed numbers were above average, lowering the mean. Choice C incorrectly assumes the removed numbers were below average, raising the mean. Choice D makes an arithmetic error in the subtraction or division.

Question 3

A data set has 10 values with a mean of 50. If each value in the data set is increased by 20%, what is the new mean?

  1. 50
  2. 60 (correct answer)
  3. 70
  4. 55
Explanation: When each value in a data set is multiplied by the same constant, the mean is also multiplied by that constant. Increasing each value by 20% means multiplying by 1.20. Therefore, the new mean is 50 × 1.20 = 60. Choice A incorrectly assumes the mean stays the same. Choice C adds 20 instead of multiplying by 1.20. Choice D adds 10% instead of 20% to the mean.

Question 4

The mean age of 6 people in a room is 25 years. If a 7th person enters and the new mean becomes 26 years, what is the age of the 7th person?

  1. 30 years old
  2. 31 years old
  3. 32 years old (correct answer)
  4. 29 years old
Explanation: The sum of ages for the original 6 people is 6 × 25 = 150 years. With 7 people and a mean of 26, the total sum becomes 7 × 26 = 182 years. The age of the 7th person is 182 - 150 = 32 years. Choice A assumes the 7th person's age equals the new mean plus the difference (26 + 4). Choice B adds an extra year due to miscounting. Choice D uses the original mean plus 4 years.