In May 2021, X Bank in the US was offering 19% interest for one-year dollar deposits. (Y Bank was offering 16.5%). Let's say you deposited 1000 dollars in the bank with 19% interest for one year in May 2021 and got 1190 dollars back in May 2022.

a)The real interest rate using the approximation formula is ..?

b)The real interest rate using the %100 correct formula is ..?

(CPI in May2021 is 532,3 and CPI in May2022 is 904,8)