Commercial Math Questions

Find the present value of a sequence of payments of $Rs.432$ made at the end of each $5$ months and continuing forever if money is worth $5\%$ compounded at the end of each $5$ months.

Which of the following statement is true regarding sinking fund and saving account?

The present value of a perpetuity is $₹50,000$ when the payment of $₹1,000$ is made at the end of each period. Find the present value of the perpetuity if the payments are made at the beginning of each period.

Nisha needs $₹2,00,000$ (after 50% subsidy) in 4 years for her daughter's education. If the interest rate is 8% p.a., how much does she need to save annually? (Assume $\frac{1.08^4-1}{0.08}=4.5$)