SOLUTION: A car made a journey of 144 miles, stopping for one hour along the way. Had it travelled at an average speed 4 mph faster and stopped for one and a half hours, it would have taken

Question 1021896: A car made a journey of 144 miles, stopping for one hour along the way. Had it travelled at an average speed 4 mph faster and stopped for one and a half hours, it would have taken the same time.
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A car made a journey of 144 miles, stopping for one hour along the way.
Had it travelled at an average speed 4 mph faster and stopped for one and a half hours, it would have taken the same time.
:
let s = actual speed
then
(s+ 4) = the faster speed
:
Write time equation; time dist/speed
+ 1 = + 1.5
subtract 1 from both sides
= + .5
multiply the equation by s(s+4)
s(s+4)* = s(s+4)* + .5s(s+4)
cancel the denominators
144(s+4) = 144s + .5s^2 + 2s
144s + 576 = 144s + .5s^2 + 2s
subtract 144s from both sides
576 = .5s^2 + 2s
Form a quadratic equation on the right
0 = .5s^2 + 2s - 576
Use the quadratic formula;

a=.5; b=2; c=-576

You can do the math, I got a positive solution of
s = 32 mph
:
:
:
See if the checks out in the original equation
+ 1 = + 1.5
4.5 + 1 = 4 + 1.5

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