Question

The altitude in feet of a plan minutes after is given by =3400 +600. How many after liftoff is the plane at an altitude of 21,000 feet?

Answer 1

a= 3400t + 600 | given formula
21000= 3400t + 600 | substitute the altitude into the formula
20400 = 3400 | subtract 600 from both sides
6 = t | divide both sides by 3400
6 minutes