Question

How does f(t)=4^t change over the interval from t=7 to t=8?

a) f(t) decreases by 4

b) f(t) increases by a factor of 4

c) f(t) decreases by 4%

d) f(t) increases by 400%

Answer 1

f(7) = 4⁷

f(8) = 4⁸ = 4·4⁷ = 4 f(7)

So f(t) increases by a factor of 4 from t=7 to t=8.

It's not A because that implies f(8) = f(7) - 4

It's not C because that implies f(8) = f(7) - 0.04 f(7) = 0.96 f(7)

It's not D because that implies f(8) = f(7) + 4.00 f(7) = 5 f(7)

Final answer: B