What lump sum must be invested at 9%, compounded monthly, for the investment to grow to $72,000 in 6 years?

Answer: $42042.50

Step-by-step explanation:

We need to use algebra and equations.

A = P x (1 + (R/n) / 100) ^nt

our amount (A) is $72K

the number of times we compound the money (n) is 12 (12 months in a year, 'compounded monthly')

our rate (R) is 9 (9%)

our time (t) is 6 (6 years)

we need to find our principal/initial amount (p)

72000 = p x (1 + 0.0075) ^12x6

p = $42042.50