Question

An airplane 30,000 feet above the ground begins descending at the rate of 2000 feet per minute. Assume the plane continues at the same rate of descent. How long will it take the plane to reach 12,000 feet above the ground

Answer 1

Explanation:

Let the time taken to reach 12,000 feet = x

Distance traveled in 1 minute = 2000 ft

Distance traveled in 'x' minute = 2000 * x = 2000x

30,000 - 2000x = 12000

Add 2000x to both sides

30,000 = 12000 + 2000x

Now subtract 12,000 from both sides

30000 - 12 000 = 2000x

2000x = 18 000

Divide both sides by 2000

x = 18000/2000

x = 9 minutes