Explanation:
2/7 miles in 2/5 hours.
to bring this to x miles / 1 hour, we must find the factor for 2/5 to turn into 1.
2/5 × f = 1
f = 5/2
in order to keep the value of the original ratio, we now need to multiply also 2/7 by the same factor (5/2).
2/7 × 5/2 = 10/14 = 5/7
so, the unit rate is 5/7 miles / hour.
which is very slow walking.