Darren drives to school in rush hour traffic and averages 28 mph. He returns home in mid-afternoon when there is less traffic and averages 42 mph. What is the distance between his home and school if the total traveling time is 1 hr 15 min?

distance between school and home is 21 miles

Explanation:

given data

in rush hour speed s1 = 28 mph

less traffic speed s2 = 42 mph

time t = 1 hr 15 min = 1.25 hr

to find out

distance d

solution

we consider here distance home to school is d and t1 time to reach at school

we get here distance equation when we go home to school that is

distance = 28 * t1 ... 1

and when we go school to home distance will be

distance = 42 * (t - t1)

distance = 42 * (1.25 - t1) ... 2

so from equation 1 and 2

28 * t1 = 42 * (1.25 - t1)

t1 = 0.75

so

from equation 1

distance = 28 * t1

distance = 28 * 0.75

distance = 21 miles