Question

Car A travels 15 mph faster than Car B. In the same time that Car A travel 165 mi, Car B travels 132mi. Find their speeds.

Answer 1

we know that,

TIME x SPEED = DISTANCE

let speed of car A = Sa

Speed of Car B = Sb

Given that, Car A travels 15 mph faster than car B

So, Sa = 15+Sb......(1)

we were also given with distances covered by both cars in same time.

SO, TIME x SPEED = DISTANCE

TIME = DISTANCE/SPEED

here both cars travel for same time So,

distance by Car A/ Sa = Distance by Car B/ Sb

165/Sa = 132/Sb

but we know from equation (1)

132 Sa = 165 Sb

132 (15+Sb)= 165 Sb

1980 +132 Sb = 165 Sb

33 Sb = 1980

Sb = 60

i.e Speed of Car B =60 mph

by substituting this value in equation 1, we get

Sa = 15+Sb

Sa = 60+15

Sa = 75 mph

Speeds of Car A = 75 mph and Car B = 60 mph