If you put away $1000 when you are 21, and you earn 10% per year every year, what will that $1000 have grown to by the time you are 77?

time = 77-21 = 50 years

amount = 1000(1.1)^50 = $ 117,390.85

To calculate the growth of the $1000 over a period of 56 years with an annual interest rate of 10%, you can use the formula for compound interest:

Future Value = Present Value * (1 + Interest Rate)^Number of Years

Plugging in the given values:
Present Value = $1000
Interest Rate = 10% or 0.10 (in decimal form)
Number of Years = 77 - 21 = 56

Now we can calculate the future value:

Future Value = $1000 * (1 + 0.10)^56

Simplifying further:

Future Value = $1000 * (1.10)^56

Using a calculator, we find that:

Future Value ≈ $1000 * 7.172173

So the $1000 will grow to approximately $7,172.17 by the time you are 77.

To calculate the future value of an investment over multiple years, you can use the formula for compound interest. The formula is:

FV = PV * (1 + r)^n

Where:
FV = Future value of the investment
PV = Present value or initial investment
r = Annual interest rate (expressed as a decimal)
n = Number of compounding periods

In this case, the present value (PV) is $1000, the interest rate (r) is 10% or 0.10, and the number of compounding periods (n) is 77 - 21 = 56 years.

Plugging in the values into the formula:

FV = $1000 * (1 + 0.10)^56

Now, we can calculate the future value of the investment:

FV = $1000 * (1.10)^56

Calculating this equation, we get:

FV ≈ $78,079.58

Therefore, by the time you are 77, the initial $1000 investment would have grown to approximately $78,079.58, assuming a consistent 10% annual interest rate compounded annually.