SAT Math Multiple Choice Practice Question 527: Answer and Explanation
5. Jennifer ran from her house to school at an average speed of 6 miles per hour and returned along the same route at an average speed of 4 miles per hour. If the total time it took her to run to the school and back was one hour, how many minutes did it take her to run from her house to school?
Correct Answer: E
E Let's plug in the answer choices, starting with C. Twenty minutes is of an hour, so (using rate × time = distance) Jennifer ran 6 × = 2 miles to school. If she returned at 4 miles per hour, you can find the time for her return trip using the formula 4 × t = 2. Her return time is hour, or 30 minutes. Her total time is supposed to be one hour, but here it's only 50 minutes. Eliminate A, B, and C because they're too small. Let's skip to E; that multiple of 6 looks like it will work better with time units than 22. Twenty-four minutes is of an hour, so Jennifer ran 6 × = 2.4 miles to school. If she returned at 4 miles per hour, you can find the time for her return trip using 4 × t = 2.4. Her return time is of an hour, or 36 minutes. Her total time is indeed one hour, so E is the answer.