# SAT Math Multiple Choice Question 551: Answer and Explanation

### Test Information

Question: 551

11. Crude oil is sold by the barrel, which refers to both the physical container and a unit of measure, abbreviated as bbl. One barrel holds 42 gallons and, consequently, 1 bbl = 42 gal. An oil company is filling an order for 2,500 barrels. The machine the company uses to fill the barrels pumps at a rate of 37.5 gallons per minute. If the oil company has 8 machines working simultaneously, how long will it take to fill all the barrels in the order?

• A. 5 hours and 50 minutes
• B. 12 hours and 45 minutes
• C. 28 hours and 30 minutes
• D. 46 hours and 40 minutes

Explanation:

A

Difficulty: Medium

Category: Problem Solving and Data Analysis / Rates, Ratios, Proportions, and Percentages

Strategic Advice: Let the units in this question guide you to the answer. You can do one conversion at a time, or all of them at once. Just be sure to line up the units so they'll cancel correctly.

Getting to the Answer: The company uses 8 machines, each of which pumps at a rate of 37.5 gallons per minute, so the rate is actually 8 × 37.5 = 300 gallons per minute. Find the total number of gallons needed, and then use the rate to find the time.

The answers are given in hours and minutes, so change 350 minutes to 350 ÷ 60 = 5.833 hours = 5 hours and 50 minutes.