GRE Mixed Quantitative Reasoning (Problem Solving) 3 — Questions and Answers
Question 1: If the average of five numbers is 18 and four of them are 12, 15, 20, and 25, what is the fifth number?
- 16
- 18 (Correct answer)
- 20
- 22
Correct answer: 18
Sum must be 90; 90 - 72 = 18.
Question 2: A rectangle has a perimeter of 36 and a length twice its width. What is its area?
- 54
- 60
- 72 (Correct answer)
- 81
Correct answer: 72
Width = 6, length = 12, so area = 72.
Question 3: If 2^(x+1) = 32, what is x?
- 3
- 4 (Correct answer)
- 5
- 6
Correct answer: 4
32 = 2^5, so x + 1 = 5 and x = 4.
Question 4: A worker is paid $15 per hour for the first 40 hours and 1.5 times that for overtime. If she earns $735 in a week, how many hours did she work?
- 46 (Correct answer)
- 47
- 48
- 49
Correct answer: 46
Regular pay = $600; remaining $135 ÷ $22.50 = 6, so total = 46 hours.
Question 5: The probability of an event is 3/8. What are the odds against it?
- 3:5
- 5:3 (Correct answer)
- 3:8
- 5:8
Correct answer: 5:3
Odds against = unfavorable:favorable = 5:3.
Question 6: If a:b = 2:3 and b:c = 4:5, what is a:c?
- 8:15 (Correct answer)
- 2:5
- 8:9
- 6:5
Correct answer: 8:15
a:b:c = 8:12:15, so a:c = 8:15.
Question 7: How many integers from 1 to 100 inclusive are divisible by both 4 and 6?
- 6
- 8 (Correct answer)
- 12
- 16
Correct answer: 8
LCM(4,6) = 12; multiples of 12 up to 100 are 12,24,...,96, which is 8.
GRE Mixed Quantitative Reasoning (Problem Solving) 3
If the average of five numbers is 18 and four of them are 12, 15, 20, and 25, what is the fifth number?