1)How much would an investor lose if she purchased a 30-year zero-coupon bond with a $ 1,000 par value and 10% yield to maturity, only to see market interest rates increase to 12% one year later?

the Right answer for this question is 19.93 Not 23.92

How can i solve the problem to get 19.93?

2)Suppose you pay $9,600 for a $10,000 Treasury bill maturing in four months. What is the effective annual rate of return for this investment? This is not a TIPS bill, but inflation is 4.5%.

And right answer for this problem is 13% how can i solve the problem to get 13%