math
posted by Al .
Jon and Remy were in a car race. When Jon finished the race in 45min, Remy had only driven 2/3 of the distance. Remy's average speed for the race was 50m/min less than Jon's.
a) Find the distance of the race.
b) What was Remy's speed?

REMY
Speed = X m/min.
d = X * 45 m.
JON
Speed = (X50) m/min.
2d/3 = (x50)*45.
Multiply both sides by 3/2:
d = 67.5(X50).
Substitute 45x for d:
45x = 67.5x  3375.
45x  67.5x = 3375.
22.5x =  3375.
b. X = 3375 / 22.5 = 150 m/min = 150m/60s = 2.5 m/s = Remy's speed.
a. d = 45x = 45min * 150m/min = 6750 m. 
Thank you.