SOLUTION: a car traveled 4032 mi at a certain speed. if the speed had been 16 mph faster, the trip could have been made in 6 hr less time. find the speed

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Question 1027194: a car traveled 4032 mi at a certain speed. if the speed had been 16 mph faster, the trip could have been made in 6 hr less time. find the speed
Found 2 solutions by lwsshak3, mananth:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
a car traveled 4032 mi at a certain speed. if the speed had been 16 mph faster, the trip could have been made in 6 hr less time. find the speed
let x=original speed
x+16=faster speed
travel time=distance /speed
4032/x-4032/(x+16)=6
lcd:x(x+16)
4032(x+16)-4032x=6x^2+96x
64512=6x^2+96x-64512
x^2+16x-10752
(x-96)(x+112)
x=96
x+16=112
original speed=96 mph
faster speed=112 mph

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!

a car traveled 4032 mi at a certain speed. let speed be xmph
if the speed had been 16 mph faster, (x+16)
the trip could have been made in 6 hr less time.

original time - time after speed increase = 6
t=d/r
4032/x - 4032/(x+16) = 6
multiply equation by x(x+16)
4032(x+16)-4032x = 6x(x+16)
4032x%2B4032%2A16-4032x+=+6x%5E2%2B96x
6x%5E2+%2B96x-64512=0
/6
x%5E2%2B16x-10752=0
x%5E2%2B16x=10752
x%5E2%2B16x%2B64=+10752%2B64
%28x%2B8%29%5E2=+64576
square root
x+8 = +/-104
x = 104-8
x=96 mph