Bluebook SAT Test Ratios, Rates, Proportional Relationships, and Units 12

Question 1

Two cars start at the same point and drive in opposite directions. Car A travels at 55 mph and Car B at 45 mph. After how many hours are they 300 miles apart?

Accepted Answer

3 hours

Answer

Combined separation rate = 55 + 45 = 100 mph; time = 300 ÷ 100 = 3 hours.

Question 2

A $200 item is marked down by 20%, then the sale price is increased by 20%. What is the final price?

Accepted Answer

$192

Answer

Sale price = $200 × 0.80 = $160; final = $160 × 1.20 = $192.

Question 3

A tank initially contains 120 liters. Water flows in at 8 L/min and drains at 5 L/min. How many minutes until the tank holds 195 liters?

Accepted Answer

25 minutes

Answer

Net fill rate = 8 − 5 = 3 L/min; needed = 195 − 120 = 75 liters; time = 75 ÷ 3 = 25 minutes.

Question 4

A runner completes 3/5 of a marathon (26.2 miles) in 2 hours. At this pace, what is her predicted finishing time in hours?

Accepted Answer

3 hr 20 min

Answer

Full race time = 2 ÷ (3/5) = 2 × 5/3 = 10/3 hours = 3 hours 20 minutes.

Question 5

A square tile has a side length of 30 cm. How many tiles are needed to cover a floor that is 6 m × 4.5 m? (1 m = 100 cm)

Accepted Answer

300

Answer

Floor area = 600 × 450 = 270,000 cm²; tile area = 30² = 900 cm²; tiles = 270,000 ÷ 900 = 300.

Bluebook SAT Practice Test

Bluebook SAT Practice Test

Bluebook SAT Test Ratios, Rates, Proportional Relationships, and Units 12