# MATH EXPONENTIAL HELP?

You have a bank account with \$150 in it. Every year, you earn 4% in interest on your account, which means that the amount of money in the account is multiplied by 1.04 each year. If you never take money from the account, how much money will be in the account after 4 years?

Relevance
•  You have a bank account with \$150 in it.

Every year, you earn 4% in interest on your account,

which means that the amount of money in the account is multiplied by 1.04 each   year. If you never take money from the account,

how much money will be in the account after 4 years?

The future amount of investment is given by:

A = P(1 + r/100)^t

where:

A = amount

P = principal

r = rate

t = time

thus the amount after 4 years will be:

A = 150(1 + 4/100)^4

A = \$175.48

• If you earn 4% every year, compounded annually, we can use this equation:

a(t) = a(1.04)^t

Where "a" is the starting amount.  We are told this is \$150, so:

a(t) = 150(1.04)^t

What's the amount after 4 years?  Solve for a(4):

a(4) = 150(1.04)^4

a(4) = 150(1.16985856)

a(4) = \$175.48 (rounded to the nearest penny)