Question

一道数学题，请解答，多谢！

Liam's goal is to save $20,000. What principal invested for 5 years at 6% per annum, compounded semi-annually, then for the next 3 years at 6.5% per annum, compounded quarterly, achieves this goal in 8 years?

Answer 1

liam想省20000元。前五年年利率6%，后三年年利率6.5%，问8年时间如何达到这个目标？
解:设需存款X元，
x(1+6%)^6(1+6.5%)^3=x+20000→x=28030.8=28031元

Answer 2

providing principal is x
then in five and a half years, principal wil be x*(1+0.06)^5*(1+0.06/2)
in the next three and a quarter years, principal wil be x*(1+0.06)^5*(1+0.06/2)*(1+0.065)^3*(1+0.065/4)
then save x*(1+0.06)^5*(1+0.06/2)*(1+0.065)^3*(1+0.065/4)-x=20000
x=28,901

Answer 3

楼上写的计息频率是错的，这里回答不方便，如果需要，直接点我，我帮你解答~