Leo invests $2,000 at an interest rate of 4%, compounded quarterly, and another $2,000 at an interest rate of 3.75%, compounded annually. How much are the investments worth in total at the end of 3 years?

Respuesta :

Investments worth $4487.19 in total at the end of 3 years.

Solution:

Principal, P = 2000

Rate, R = 4% compounded quarterly

Rate, R = 3.75% compounded annually

Year, n = 3

Formula for compound interest when compounded quarterly:

[tex]Amount=P(1+\frac{\frac{R}{4} }{100})^{4n}[/tex]

Substitute P = 2000, R = 4% and n = 3

[tex]Amount=2000\times(1+\frac{\frac{4}{4}}{100})^{4\times3}[/tex]

              [tex]=2000\times(1+\frac{1}{100})^{12}[/tex]

              [tex]=2000\times(\frac{100+1}{100})^{12}[/tex]

              [tex]=2000\times(\frac{101}{100})^{12}[/tex]

              = 2253.65

Amount when compound interest calculated quarterly is 2253.65.

Formula for compound interest when compounded annually:

[tex]Amount=P(1+\frac{R}{100})^{n}[/tex]

Substitute P = 2000, R = 3.75% and n = 3

[tex]Amount=2000\times(1+\frac{3.75}{100})^{3}[/tex]

              [tex]=2000\times(\frac{100+3.75}{100})^{3}[/tex]

              [tex]=2000\times(\frac{103.75}{100})^{3}[/tex]

              = 2233.54

Amount when compound interest calculated annually is 2233.54.

Total amount = 2253.65 + 2233.54

                      = 4487.19

Hence, investments worth $4487.19 in total at the end of 3 years.