Question

1. an airplane that is flying at an altitude of 30,000 feet is beginning to descend at a rate of 1,000 feet per minute. a helicopter is beginning its trip, starting at an altitude of zero feet. the helicopter ascends more slowly than the airplane, going up at a rate of 500 feet per minute. after how many minutes will the airplane and the helicopter be at the same altitude?

a. 10
b. 15
c. 20
d. 30
e. 60

Explanation:

Step1: Define variables and equations

Let $t$ = time in minutes.
Airplane altitude: $30000 - 1000t$
Helicopter altitude: $0 + 500t$

Step2: Set altitudes equal

$30000 - 1000t = 500t$

Step3: Solve for $t$

$30000 = 500t + 1000t$
$30000 = 1500t$
$t = \frac{30000}{1500}$

Answer:

C. 20