The expression 1,000(1.0215)4t represents the amount of money in an account after t years. the interest is compounded , and the effective annual interest rate on the account is .

Rate = r= 8.6 %

Step-by-step explanation:

For compound interest

A= P( 1 +r/n)⁴t= 1000(1.0215)⁴

from above we have 1.0215= 1+ 0.0215= 1+r/4

0.0215=r/4

r= 0.0215 *4=0.086= 8.6 %

where A is the amount

P= Principal

interest Rate= r

n= number of times interest is applied per year

t= number of years (time)

for t= 1

A= 1000(1.0215)⁴= 1000(1.0888) =$ 1088.813

for t= 2

A= 1000(1.0215)⁸= 1000( 1.18554)=  $1,185.515