algebra help

Question

Car A and car B are traveling at different speeds. Car A can travel 120 miles in the same time it takes car B to travel 105 miles. If car A travels 10 mph faster than car B, how fast (in mph) is car B traveling?

Answer 1

v = speed of car A

u = speed of car B

 

vt = 120

ut = 105

 

These 2 equations ⇒ 

 

v/u = 120/105 ⇒ v = (120/105)u

 

v = u + 10

 

(120/105)u = u + 10

 

[(120/105) - 1]u = 10

 

u = 70 mph

v = 70 + 10 = 80 mph