If you drive to your spring break destination at a steady 60 miles per hour and return at a steady 40 miles per hour what is your average speed for the round trip?

D = distance to & from spring break destination

t1 = d/60 = time to get there

t2 = d/40 = time to get back

avg speed = (total distance)/(total time)

= 2d/(d/60+d/40)

Divide numerator and denominator by d:

= (2/(1/60 + 1/40))

Multiply numerator and denominator by 120:

= 240/(2 + 3)

= 240/5

= 480/10

= 48 mi/hr is the average speed round trip.
Trentt31