...can someone please check if this answer is correct or did I do any mistake in between?

Ms. Halliday received a mortgage loan from the Bank of Nova Scotia for $60,000 at 11.25% compounded semi-annually for a five-year term. Monthly payments were based on a 20 year amortization period.

The periodic payment, often referred to as the rent, is what must be paid, knowing only the present value, interest rate and the number of payment periods.

Example: What is the periodic payment required to retire a debt of P dollars in n periods (months or years) if payments start at the end of the first period and bear I% interest compounded periodically? For this typical loan payment calculation,

......................R = Pi/[1 - (1 +i)^(-n)]

where R = the rent (periodic payment), P = the amount borrowed, n = the number of payment periods, and i = I/100.

Example: What is the annual payment required to retire a loan of $10,000 over a period of 5 years at an annual interest rate of 8%? Here, P = 10,000, n = 5, and i = .08 resulting in

...........................R = 10000(.08)/[1 - (1.08)^-5] = $2504.56 per year

For your case, the monthly payment required to retire a debt of $60,000 over a 20 year period at 11.25% interest compounded monthly is

R = Pi/[1 - (1 +i)^(-n)] where P = 60,000, i = .1125/12 = .009375)(interest compounded monthly, the same period of time as payments are made) and n = 20(12) = 240

R = 60,000(.009375[1 - (1.009375)^(-240))] = $502.59.