SOLUTION: On a drive from your home to town, you wish to average 33.6 mph. The distance from your home to town is 90 miles. However, at 45 miles (half way), you find you have averag

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: On a drive from your home to town, you wish to average 33.6 mph. The distance from your home to town is 90 miles. However, at 45 miles (half way), you find you have averag      Log On

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Question 788754: On a drive from your home to town, you wish
to average 33.6 mph. The distance from your
home to town is 90 miles. However, at 45 miles
(half way), you find you have averaged only
25.2 mph.
What average speed must you maintain in
the remaining distance in order to have an
overall average speed of 33.6 mph?
Answer in units of mph
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
On a drive from your home to town, you wish
to average 33.6 mph. The distance from your
home to town is 90 miles. However, at 45 miles
(half way), you find you have averaged only
25.2 mph.
What average speed must you maintain in
the remaining distance in order to have an
overall average speed of 33.6 mph?
Answer in units of mph
let the speed be x
total average = 33.6
distance = 90
time = 90/33.6
Time first leg = 45/25.2
Time second leg= 45/x
45/25.2 + 45/x = 90/33.6

45/x = 90/33.6 - 45/25.2
45/x = 0.893
x= 45/0.893
x=50.49 mph