Leon drove from his house in Cincinnati to his sister’s house in Cleveland, a distance of 252 miles. It took him 4.5 hours. For the first half-hour, he had heavy traffic, and the rest of the time his speed was five miles per hour less than twice his speed in heavy traffic. What was his speed in heavy traffic?

Speed in heavy traffic is 32 miles per hour

Step-by-step explanation:

Total distance = 252miles

Total time = 4.5hours = 4 hours + 30minutes

Let the speed in heavy traffic = x

distance = time * speed

First half hour    

D1 = 0.5*x

The speed after the traffic = 2x - 5

D2= 4* (2x - 5)  

Total distance = D1 + D2

     + 8x - 20 = 252

          = 272

      x =

      x = 32 miles per hour

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!