Ruth Lewis deposited $$2,800$ today in an account paying $7$ percent interest annually. $($Round answers to $0$ decimal places, e$.$g$.5,713.$

a$.$ What would be the simple interest earned on this investment in $5$ years?

Simple interest on investment $

b$.$ With annual compounding, how much interest$-$on$-$interest would Tina earn in $5$ years?

Interest$-$on$-$interest $