GMAT Quantitative: Algebraic Word Problems 3 — Questions and Answers
Question 1: A store marks up a $40 item by 50%, then offers 20% off the marked price. What is the final price?
- $48 (Correct answer)
- $44
- $52
- $50
Correct answer: $48
40 × 1.5 = 60, then 60 × 0.8 = 48.
Question 2: The average of 5 numbers is 14. If a sixth number is added and the average becomes 16, what is the sixth number?
- 26 (Correct answer)
- 16
- 20
- 30
Correct answer: 26
New total is 6 × 16 = 96, old total is 70, so the sixth number is 26.
Question 3: A boat travels 30 miles downstream in 2 hours and returns upstream in 3 hours. What is the speed of the current?
- 2.5 mph (Correct answer)
- 5 mph
- 1.25 mph
- 3 mph
Correct answer: 2.5 mph
Downstream 15 = b+c, upstream 10 = b−c, so c = 2.5.
Question 4: If a number is tripled and then 7 is subtracted, the result is 20. What is the number?
- 9 (Correct answer)
- 7
- 11
- 13
Correct answer: 9
3x − 7 = 20 gives 3x = 27, so x = 9.
Question 5: Two cars start from the same point traveling in opposite directions at 50 and 60 mph. After how many hours are they 330 miles apart?
- 3 (Correct answer)
- 4
- 2.5
- 5
Correct answer: 3
110t = 330, so t = 3.
Question 6: A mixture of 20 liters is 30% acid. How many liters of pure acid must be added to make it 50% acid?
- 8 (Correct answer)
- 10
- 6
- 4
Correct answer: 8
(6+x)/(20+x) = 0.5 gives x = 8.
Question 7: Five years ago a father was 4 times as old as his son. Now he is 3 times as old. How old is the son now?
- 15 (Correct answer)
- 10
- 12
- 8
Correct answer: 15
3s − 5 = 4(s − 5) gives s = 15, so the son is 15 now.
GMAT Quantitative: Algebraic Word Problems 3
A store marks up a $40 item by 50%, then offers 20% off the marked price.
What is the final price?