$3.$ A treasury bill $($T$-$bill$)$ is a type of bond that is sold at a discount over the face value. Suppose you buy a $13-$week T$-$bill with a face value of $$10,000$ for $$9,800.$ This means that in $13$ weeks, you can redeem it for the face value, earning you $$200.$ What annual interest rate do you earn? $($Hint: $13$ weeks is a quarter of a year.$)$