Question 1027194


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+4032*16-4032x = 6x^2+96x}}}

{{{6x^2 +96x-64512=0}}}

/6

{{{x^2+16x-10752=0}}}

{{{x^2+16x=10752}}}

{{{x^2+16x+64= 10752+64}}}

{{{(x+8)^2= 64576}}}

square root

x+8 = +/-104

x = 104-8

x=96 mph