SOLUTION: a man made a trip of 432 miles by car. if the average speed had been 6 miles per hour faster, the trip would have taken one hour less. how long did the trip take and what was his a

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Question 1031723: a man made a trip of 432 miles by car. if the average speed had been 6 miles per hour faster, the trip would have taken one hour less. how long did the trip take and what was his average speed?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
speed x
speed x + 6

Distance = same 432 km 1
original time – time with increased speed = 1 hour
t=d/t
432 / x - 432 / ( x + 6 ) = 1
LCD= x ( x + 6 )
multiply by LCD
432 ( x + 6 ) - 432 x = 1 x ( x + 6 )
432 x + 2592 - 432 x = 1 X^2 + 6 x
2592 = x^2 + 6 x
x^2 + 6 x - -2592 = 0
x^2 +6x +9 = 2592+9
(x+3)^2 =2601
(x+3) = +/- 2601
x+3 = +/- 51
x= 51-3 = 48 km/h