Question

Interpreting Functions in the Real World
A hot air balloon descends to the ground. The function a(t) = 210 – 15t can be used to describe the altitude of the balloon as it approaches the ground. The time is in minutes.

What does t represent?


What does a(t) represent?


What information will a(5.5) give?

Answer 1

- t represents the time in minutes since the start of the descent (i.e., the elapsed time in minutes).
- a(t) represents the balloon’s altitude above the ground at time t (in the same units as the number 210).
- a(5.5) is the altitude after 5.5 minutes: a(5.5) = 210 − 15(5.5) = 127.5 (units).