Show this for both present and future values.

Calculating EAR A check$-$cashing store is in the business of making personal loans to walk$-$up customers. The store makes only one$-$week loans at $6\mathrm{.}3$ percent interest per week.

$$The check$-$cashing store also makes one$-$month add$-$on interest loans at $6\mathrm{.}3$ percent discount interest per week. If you borrow $$100$ for one month $($four weeks$),$ the interest will be $($$$1001\mathrm{.}063*)-100=$ $$27\mathrm{.}68.$ Because this is discount interest, your net loan proceeds today will be $$72\mathrm{.}32.$ You must then repay the store $$100$ at the end of the month. To help you out, though, the store lets you pay off this $ $100$ in installments of $$25$ per week. What is the APR of this loan? What is the EAR?