Question

What model describes the relationship between the amount of money in an account and time, given that the money triples every month?
a. linear
b. quadratic
c. cubic
d.exponential

Answer 1

Firs month         A

Second month  3A

Third month      3*3A = A (3^2)

Fourth month    A(3^3)

Fith month        A (3^4)

nth month        A (3 ^ (n-1) )

That is an exponential model, because the variable (time, n) is the exponent of the formula. 

Answer 2

It is exponential. The money triples therefore the money grows exponentially. :)