Suppose your friend's parents invest $20,000 in an account paying 5% compounded annually. What will the balance be after 66 years?

What is 20000(1.05)^66 ?

500637.911743

is that the answer?

Yes, except since this is money in dollars you would round it to the nearest cent.

$500,637.91

To find the balance after 66 years, we can use the formula for compound interest:

A = P(1 + r/n)^(nt)

Where:
A = the future value of the investment (balance)
P = the principal amount (initial investment)
r = the annual interest rate (as a decimal)
n = the number of times the interest is compounded per year
t = the number of years

Given:
P = $20,000
r = 5% (or 0.05 as a decimal)
n = 1 (since it is compounded annually)
t = 66 years

Now we can plug these values into the formula and solve for A:

A = 20,000(1 + 0.05/1)^(1*66)
A = 20,000(1 + 0.05)^(66)
A = 20,000(1.05)^(66)

Calculating this using a calculator or a computer, the final balance (A) will be approximately:

A ≈ $426,557.68

Therefore, the balance will be around $426,557.68 after 66 years.