Question

Diane averages 10 mph riding her

bike to work. Averaging 40 mph
on the way back home by car, she
takes hour less time.
How far does she travel
to work?

Answer 1

20 miles

Explanation:

d miles × (1 h)/(10 miles) = d/10 hours

d miles × (1 h)/(40 miles) = d/40 hours

d/40 = d/10 - 3/2

d = 4d - 60

d = 20 miles