Bluebook SAT Test SAT Word Problems Practice 8

Question 1

A population of bacteria doubles every 3 hours. Starting with 500 bacteria, how many will there be after 12 hours?

Accepted Answer

8,000

Answer

12 hours = 4 doubling periods. Count = 500 × 2⁴ = 500 × 16 = 8,000.

Question 2

A cyclist rides 15 mph for part of a 60-mile trip and 10 mph for the rest. The trip takes 5 hours. How many miles did the cyclist ride at 15 mph?

Accepted Answer

30

Answer

d/15 + (60−d)/10 = 5 → multiply by 30: 2d + 3(60−d) = 150 → −d = −30 → d = 30.

Question 3

Three consecutive odd integers have a sum of 51. What is the product of the largest and smallest?

Accepted Answer

285

Answer

n + (n+2) + (n+4) = 51 → n = 15. Smallest = 15, largest = 19. Product = 15 × 19 = 285.

Question 4

A school has 850 students. Each takes math, science, both, or neither. 600 take math, 500 take science, and 100 take neither. How many take both?

Accepted Answer

350

Answer

Students in at least one = 750. By inclusion-exclusion: 600 + 500 − both = 750 → both = 350.

Question 5

A shirt costs $45. It is discounted 20%, then an additional 10% off the sale price. What is the final price?

Accepted Answer

$32.40

Answer

After 20% off: $36. After 10% off that: $36 × 0.90 = $32.40.

Bluebook SAT Practice Test