$*$Use formula from the formula sheet. ROR $\%=($current value of portfolio $-$ previous value of portfolio$)/($previous value of portfolio$)100$

Question $8(1$ point$)$

Khaled is planning to buy a new piano. He intends to spend no more than $$8000.$ He has $$6250$ to invest in an account that pays $4\mathrm{.}6\%,$ compounded annually. How long will it take Khaled to meet his goal?