Hello, Seirin!

This is an Amortization . . .A mortgage is taken out for $80,000.

It is to be paid by annual installments of $5000 with the first payment

being made at the end of the first year that the mortgage was taken out.

Interest of 4% is then charged on any outstanding debt.

Find the total time taken to pay off the mortgage.

The answer given is 25 years. . . . . I don't agree

The formula is: .

. . where: .

We have: .

Then: .

. .

Take logs: .

Therefore: .