Question

On a steeper slope, the jogger can run at an average speed of 5.3 miles per hour up the slope and 6.7 miles per hour going down the slope.

How long, in hours, the full trip will take (1 mile uphill and 1 mile downhill). Give an exact answer expressed as a fraction in simplest terms and then give a decimal approximation correct to three decimal places. (Hint: Use the same method as in #1.)

Reduced Fraction: _________ Decimal Approximation: _________

Answer 1

On a steeper slope, the jogger can run at an average speed of 5.3 miles per hour up the slope and 6.7 miles per hour going down the slope.

distance = rate times time.

In this problem, distance = 1 mile = rate times time

In the first case, the rate is 5.3 mph, so 1 mile= (5.3 mph)(time), and (time) =

1 mile
----------- = 0.189 hour
5.3 mph

In the second case, the rate is 6.7 mph, and

1 mile
----------- = 0.149 hour
6.7 mph

The total transit time (up and down) is 0.189 hour plus 0.149 hour, or

0.338 hour, or 20.3 minutes.