!!!! PLEASE HELP!!!!!
Taking into account reaction time, the distance d (in feet that a car requires to come to a complete stop while traveling r miles per hour is given by the following function.

d(r)=6.97r-90.33

a) express the speed r at which the care is traveling as a function of the distance d required to come to a complete stop. verify your answer by checking that r(d(r))=r, d(r(d))=d
r(d)=_________
b) predict the speed that a car was traveling if the distance required to stop was 330 feet.
The car was traveling approximately _______
miles per hour. (round to the nearest whole number)

Question

!!!! PLEASE HELP!!!!!
Taking into account reaction time, the distance d (in feet that a car requires to come to a complete stop while traveling r miles per hour is given by the following function.

d(r)=6.97r-90.33

a) express the speed r at which the care is traveling as a function of the distance d required to come to a complete stop. verify your answer by checking that r(d(r))=r, d(r(d))=d
          r(d)=_________
b) predict the speed that a car was traveling if the distance required to stop was 330 feet.
         The car was traveling approximately _______
          miles per hour. (round to the nearest whole number)

dumbcow · Answer

$$r = \frac{d+90.33}{6.97}$$
d = 330
$$r = \frac{330+90.33}{6.97} = 60.3$$

anonymous · Answer

Thank you SUPER MUCH!