I am so lost....

Mario decided to invest his $620 tax refund rather than spending it. He found a bank that would pay him 4% interest, compounded quarterly. Mario deposits the entire $620 refund and does not deposit or withdraw any other amount.

a. Write an equation that models the growth of the investment.
b. How many years will it take for the initial investment to double?

Question

I am so lost....

Mario decided to invest his $620 tax refund rather than spending it. He found a bank that would pay him 4% interest, compounded quarterly. Mario deposits the entire $620 refund and does not deposit or withdraw any other amount.

a.	Write an equation that models the growth of the investment.
b.	How many years will it take for the initial investment to double?

anonymous · Answer

You need to use the formula A=P(1+r/n)^nt
For part B set A equal to 1240 and solve for time

P = principal amount (the initial amount you borrow or deposit)
620
r  = annual rate of interest (as a decimal)
.04
t  = number of years the amount is deposited or borrowed for.
A = amount of money accumulated after n years, including interest.
1240 for part b
n  =  number of times the interest is compounded per year 
4

anonymous · Answer

thank you Tutor Delphia