If a lender makes a simple loan of $$400$ for $2$ years and charges $8\%,$ then the amount that the lender receive at maturity is $ $($Round your response to the nearest two decimal place$)$

If a lender makes a simple loan of $$2500$ for one year and charges $$90$ interest, then the simple interest rate on that loan is $\%.($Round your response to the nearest whole number$)$