Question

7. The amount of water in a tank decreases at a rate of 7% per day. The amount of water in the tank was originally

3,500 cubic inches. Which function models the amount of water in cubic inches left after d days?
A 0.93(3,500)
B 1.07(3,500)
C 3,500 (0.93)
D 3,500(1.07)

Answer 1

C:

3500(0.93)^d

Exponential functions have the form a·b^x, where:

a is the initial amount

b is the percent remaining after each time period

a = 3500, since that's the original volume.

Since 7% is lost each day, 93% remains, so b=0.93.