I need help

Jessica is a custodian at oracle arena. she waxes 20 m2 of the floor in 3/5 of an hour. jessica waxes the floor at a constant rate. at this rate how many sqaures meters can she wax per hour

Need solving this second acceleration problem.

Estimate the area under the curve f(x) = 16 - x^2 from x = 0 to x = 3 by using three inscribed (under the curve) rectangles. answer to the nearest integer.