Aschool custodian waxed a gymnasium floor that measured 20 feet by 20 feet. how many square feet did she have to wax? a. 40 square feet b. 400 square feet c. 80 square feet end of exam d. 800 square feet

I'm terrible at math any here is appreciated.

The physical fitness of an athlete is often measured by how much oxygen the athlete takes in (which is recorded in milliliters per kilogram, ml/kg). the mean maximum oxygen uptake for elite athletes has been found to be 60 with a standard deviation of 7.2. assume that the distribution is approximately normal.

Ateacher has $80 to buy workbooks. each work book cost $3. if she buys as many workbooks as possible, how much money does she have leftover? a) $2 b) $4 c) $6 d) $8