gmatbusters wrote:

A race car can travel 120 mph without any wind. If the car can travel 200 miles with the wind in the same amount of time the car takes to go 100 miles against the wind, what is the speed of the wind?

A) 24 mph

B) 30 mph

C) 40 mph

D) 45 mph

E) 60 mph

GMATbuster's Weekly GMAT Quant Quiz #5 Ques No 5

Time = Distance/Speed

We are given the time is equal

\(\frac{200}{(120+w)} = \frac{100}{(120-w)}\)

cross multiply we get \(200*120 - 200w = 120*100 + 100w\)

it becomes\(2*100*120 - 100*120 = 300w\)

\(100*120 = 300w\)

\(120 = 3w\)

w = 40

Answer choice C