Math: !If 4000 dollars is invested in a bank account at an interest rate of 7 per cent per year,

Find the amount in the bank after 8 years if interest is compounded monthly

Please help!!!

there's a formula for this just plug in the numbers. 7%=0.07, 12 months peryearx 8 yrs= 96 mnths. pretty straightforward i forgot the formula but you could still crank it out the old fashion way.

With an interest rate of 7% per year, compounding monthly means you have 12 periods per year earning 7/12 of a percent in each period. Since it's a percent, you need to divide by 100 to get the rate as a number you can use (i.e. 7% = 0.07). Since we have a fraction I'm going to leave it that way, since decimal form would have a rounding error. So the interest added in each period is 7/1200 of the principal at the start of that period. In other words, the new principal is the old principal plus 7/1200 of the old principal.

Writing that out mathematically, we can say:

Pn = Po + 7/1200 * Po
(where Pn is the new principal and Po is the old principal)

We can rewrite this to group the Po's together:

Pn = (1 + 7/1200) * Po

There are 104 months (periods) in 8 years. You can do this the hard way by multiplying it out 104 times, but it's easier to use an exponent, because all we need to do is apply the interest 104 times. So we get

Pn = (1 + 7/1200)^104 * Po

Plugging that into a calculator will give you your answer.

Well if it goes up by 7% every year you have to multiply $4000 by 1.07

so you do $4000 * 1.07

but as you need to find much it is after 8 years you have to do

$4000 * 1.07(to the power of 8)

4 000 * (1.07^8) = 6 872.74472

answer = $6 872. 74

it sounds difficult but there is a very simple way

you just do $4000 x 1.07 ^ 8