Barbara bought a 91-day T-bill that has an interest rate of 4.30% p.a. and a face value of $5,000.

1. How much did she pay for the T-Bill?
2. 
   
3. After 40 days, Barbara sold the T-bill to her friend when the interest rate for this T-bill in the market increased to 5.30% p.a. 
4. 
   
5. What was her selling price?