Question

Petra jogs 5 miles in 40 minutes. At this rate, how long would it take her to jog 7 miles?

Answer 1

You could write and solve an equation of ratios:

    5 mi          7 mi
------------ = ----------
 40 min           x

Then 5x = 280, and x = 56.  Petra can jog 7 miles in 56 minutes.

Answer 2

(40 min)/(5 mi) = (time)/(7 mi) . . . . . the rates are the same
(7/5)*(40 min) = time = 56 min

At the same rate, it would take Petra 56 minutes to jog 7 miles.