A runner wants to run 13.1 km. She knows that her running pace is 6.2 mi/h. How many minutes must she run? Hint: Use 6.2 mi/h as a conversion factor between distance and time.

79 minutes

Explanation:

1) Convert the distance, 13.1 km to miles

Conversion factor:

1 = 1 mi / 1.61 km

13.1 km [ 1 mi / 1.61 km ] = 8.1336 mi

2) Use 6.2 mi/h as a converstion factor between distance and time

8.1366 mi * 1 / [6.2 mi/h] = 1.3124 h

3) Convert 1.3124 h to minutes

1.3124 h * [ 60 min/h] = 78.7 min

Rounding to the nearest minutes (two significant figures):

79 min ← answer