PSAT Math Grid-Ins Question 39: Answer and Explanation

Question: 39

The graph above shows the amount of time, in hours, that Robert spends jogging in each month through a particular year. The information for the month of December is not included in the graph.

In November, Robert jogged at an average pace of 8 miles per hour. In December, Robert ran for h hours at an average pace of 7 miles per hour. If the total distance that Robert jogged each of the two months was the same, what is the value of h?

Correct Answer: 160

Explanation:

160

The question asks for the value of h, which is the number of hours jogged during the month of December. The question says that the total distance jogged each of the two months was the same. Find the distance jogged in November. The question says that Robert jogged at an average pace of 8 miles per hour, and the chart says that he jogged for 140 hours. To find the total distance, multiply the rate by the time to get 8 × 140 = 1,120 miles. In December, the rate is 7 miles per hour and the total distance is also 1,120. To find the time, set up the equation 1,120 = 7h. Divide both sides by 7 to get h = 160. The correct answer is 160.