Question

Denise can ride her bike 12 mph in calm water. It takes her as long to ride 75 miles with the wind as it take her 45 miles against the wind. What is the speed of the wind

Answer 1

The correct answer is 3 miles per hour.

Explanation:

Let the speed of the wind be x miles per hour.

Speed of Denise in her bike is 12 miles per hour.

Time taken to travel 75 miles by Denise to bike with the wind is
`(75)/(12+x)`.

Time taken to travel 45 miles by Denise to bike against the wind is
`(45)/(12-x)`.

These time is given to be same.

∴ 75 × (12 - x) = 45 × (12 + x)

⇒ 900 - 75x = 540 + 45x

⇒ 360 = 120x

⇒ x = 3

Thus the speed of the wind is 3 miles per hour.