Question

The altitude a (in feet) of a plane t minutes after liftoff is given by a=3,400t +600 . How many minutes after liftoff is the plane at an altitude of 21,000 feet?

Answer 1

6 minutes

Explanation:

a=3400t+600 substitute 21000 for a

21000=3400t+600 subtract 600 from both sides

20400=3400t divide by 3400

6=t