Determine the principal that must be invested at 7% compounded monthly, so that $500,000 will be available for retirement in 49 years.

Answer in units of dollars

x*((1 + .07/12)^(49*12)) = 500,000

Solve for x

16356

To find the principal amount that must be invested, we can use the compound interest formula:

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

where:
A = final amount ($500,000 in this case)
P = principal amount
r = annual interest rate (7% or 0.07 in decimal form)
n = number of times interest is compounded per year (monthly compounding, so n = 12)
t = number of years (49 years in this case)

Rearranging the formula to solve for P:

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

Now we can substitute the known values into the formula and calculate the principal amount.

P = 500,000 / (1 + 0.07/12)^(12*49)

First, let's calculate the term in the parentheses:

(1 + 0.07/12)^(12*49) = 1.00583^588 = 132.16089

Now, divide the initial amount by this result:

P = 500,000 / 132.16089 ≈ $3,783.35

Therefore, the principal amount that must be invested at 7% compounded monthly, so that $500,000 will be available for retirement in 49 years, is approximately $3,783.35.