Using compound interest, it is found that he must deposit $56,389.
Compound interest:
- A(t) is the amount of money after t years.
- P is the principal(the initial sum of money).
- r is the interest rate(as a decimal value).
- n is the number of times that interest is compounded per year.
- t is the time in years for which the money is invested or borrowed.
In this problem:
- Hopes to have $80,000 in 20 years, thus
.
- Interest rate of 1.75%, thus
.
- Compounding monthly, thus
- The investment is of P, for which we have to solve.
Then:
He must deposit $56,389.
A similar problem is given at brainly.com/question/25263233