Problema Solution
Andrew drove 350 miles to see a friend. On the trip returning he drove through bad weather and drove 20 miles per hour slower than going. If the return trip took 2 hours longer, and the time going was 5 hours, at what speed did he drive each way?
Answer provided by our tutors
let
v1 = the going speed
v2 = the returning speed trough bad weather
d = 350 miles the distance Andrew draw one way
t1 = 5 hours the time going
t2 = the returning time
on the trip returning he drove through bad weather and drove 20 miles per hour slower than going
v2 = v1 - 20
the return trip took 2 hours longer then the going
t2 = t1 + 2 = 5 + 2 = 7 hours
since speed = distance/time => distance = time*speed
t1*v1 = d
5v1 = 350 => v1 = 350/5
v1 = 70 mph
t2*v2 = d
7v2 = 350 => v2 = 350/7
v2 = 50 mph
the going speed of Andrew was 70 mph and the returning speed was 50 mph.