John bought a pair of shoes on sale for $60. They were originally priced at $75. What is the markdown percent of the shoes?

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?

52 cm radius = diameter = area = circumference = circumfer

The mass of a marine organism, in pounds, p years after it is born is given by the polynomial function r(p) = -4p2 + 300p. find the mass when p = 20 years.