Question

A bank charges a fee of 0.5% per month for having a checking account. Stephani’s account has $325 in it. Which function models the balance of Stephani’s account, B(t), in dollars, as a function of time, t, in months?
a: B(t) = 325(0.0995)t

b: B(t) = 325(0.005)t

c: B(t) = 0.05(325)t

d: B(t) = 325 + 12(0.005)t

Answer 1

Answer:

$f(t) = 325(0.995)^t$

Step-by-step explanation:

Given

$r= 0.5\%$ ---- Charges

$a= \ 325$ --- Amount

Required

Represent the balance as a function

This is calculated using exponential function.

$f(t) = ab^t$

Where

$b = 1 - r$

So, we have:

$b = 1 - 0.5\%$

$b = 1 - 0.005$

$b = 0.995$

So:

$f(t) = ab^t$

$f(t) = 325 * 0.995^t$

$f(t) = 325(0.995)^t$