Question

If $4200 is invested in a savings account for which interest is compounded

Answer 1

Answer:

3.9%

Step-by-step explanation:

The formula for compound interest to apply is;

$A=P(1+\frac{r}{n} )^{nt}$

where;

A=amount at the end

P=starting amount/principal

n=number of compounding years

t=total number of years

r=interest rate expressed as a decimal

Given

P=$4200, n=2, t=4 and A=$4900 R=?

Substitute values in equation, take r=r

$A=P(1+\frac{r}{n} )^{nt} \\\\\\4900=4200(1+\frac{r}{2} )^{2*4} \\\\\\4900=4200(1+0.5r)^8$

Divide both sides by 4200

$\frac{4900}{4200} =\frac{4200}{4200} (1+0.5r)^8\\\\\\1.1667=(1+0.5r)^8$

Introduce root 8 to the left hand side, thus eliminating the power 8 in the right hand side

$\sqrt[8]{1.1667} =1+0.5r\\\\\\1.0195=1+0.5r\\\\\\1.0195-1=0.5r\\\\\\0.0195=0.5r\\\\\\\frac{0.0195}{0.5} =\frac{0.5r}{0.5} \\\\\\0.039=r$

r=3.9%

Answer 2

Answer:

3.89

Step-by-step explanation:

Give a <3 ?