You buy a zero-coupon bond that has a face value of $1,000, 5 years to maturity, and a yield to maturity of 7.3%. How do you get the purchase price of the bond?

If one year later similar bonds are offering a yield to maturity of 8.1%. You decide to sell the bond now. How do you find what the current price of the bond is and the interest income?

Assume a tax rate of 40% on regular income and 15% on capital gains.

How do you find the capital gain (or loss) on the bond and then the before-tax rate of return on the investment?

This is a sample question where we already have the solutions but not the workings.