Question

An airplane is at 32,000 ft above sea level and descends at an average rate of 1,000 ft per minute. How many minutes will it take the plane to land 3,000 ft above sea level?

Answer 1

29 minutes-  at a rate of 1,000 feet a minute, it would take 32 minutes to reach sea level (32,000/1000=32)but if you subtract 3000 from 32000 to remain 3000 feet above sea level, you have 29000 feet to descend which will take 29 minutes

Answer 2

Let

x-------> the time in minutes

y-------> the height of the airplane above sea level in feet

we know that

$y=32,000-1,000x$ -------> equation $1$

In this problem

For $y=3,000\ ft$

Find the value of x

Substitute the value of y in the equation $1$ and solve for x

$3,000=32,000-1,000x$

$1,000x=32,000-3,000$

$1,000x=29,000$

$x=29,000/1,000$

$x=29\ minutes$

therefore

the answer is

$29\ minutes$