Problema Solution
Jenny drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 12 hours. When Jenny drove home, there was no traffic and the trip took 8 hours. If her average rate was 20 miles per hour faster on the trip home, how far away does Jenny live from the mountains?
Do not do any rounding.
Answer provided by our tutors
let
t1 = 12 hr the time of the trip on the way up
t2 = 8 hr the time of the tip on the way down
v1 = the avg. rate on the way up
v2 = the avg. rate on the way down
her average rate was 20 miles per hour faster on the trip home
v2 = v1 + 20
since avg.rate = distance/time => distance = avg.rate*time
the distance of the trip up = the distance of the trip down
t1*v1 = t2*v2
12*v1 = 8*(v1 + 20)
by solving the equation we find
v1 = 40 mph
click here to see the step by step solution of the equation
the distance = v1*t1 = 40*12 = 480 miles
Jenny lives 480 miles far from the mountains.