GMAT Quantitative: Ratios and Proportions 2 — Questions and Answers
Question 1: The ratio of cats to dogs in a shelter is 5:3. If there are 40 animals total, how many are dogs?
- 15 (Correct answer)
- 24
- 12
- 18
Correct answer: 15
Total parts = 5+3 = 8, so each part = 40/8 = 5, and dogs = 3 x 5 = 15.
Question 2: If a/b = 4/7, what is the value of (a+b)/b?
- 11/7 (Correct answer)
- 11/4
- 7/11
- 4/11
Correct answer: 11/7
(a+b)/b = a/b + 1 = 4/7 + 7/7 = 11/7.
Question 3: Two numbers are in the ratio 3:5 and their sum is 64. What is the larger number?
- 40 (Correct answer)
- 24
- 32
- 45
Correct answer: 40
Each part = 64/8 = 8, so the larger number = 5 x 8 = 40.
Question 4: A recipe uses flour and sugar in the ratio 7:2. To make a batch with 21 cups of flour, how much sugar is needed?
- 6 cups (Correct answer)
- 3 cups
- 9 cups
- 14 cups
Correct answer: 6 cups
21/7 = 3 scaling factor, so sugar = 2 x 3 = 6 cups.
Question 5: If 12 workers can build a wall in 10 days, how many days would 15 workers take (inverse proportion)?
- 8 (Correct answer)
- 12
- 9
- 7.5
Correct answer: 8
Work = 12 x 10 = 120 worker-days, so 120/15 = 8 days.
Question 6: The ratio of x to y is 2:9. If y = 36, what is x?
- 8 (Correct answer)
- 16
- 4
- 18
Correct answer: 8
x/36 = 2/9 means x = 36 x 2/9 = 8.
Question 7: A map scale is 1:50,000. Two towns are 6 cm apart on the map. What is the actual distance in km?
- 3 km (Correct answer)
- 30 km
- 0.3 km
- 300 km
Correct answer: 3 km
6 x 50,000 = 300,000 cm = 3,000 m = 3 km.
GMAT Quantitative: Ratios and Proportions 2
The ratio of cats to dogs in a shelter is 5:3.
If there are 40 animals total, how many are dogs?