Suppose y varies directly as x and y equals 21 when x = 3 find x when y = 42

Rosy waxes 2/3 of her car with 1/4 bottle of car wax. at this rate, what fraction of the bottle of car wax will rosey use to wax her entire car

Fanny mendelssohn manages all the magazines and paperback books at a local grocery store. she prices many paperbacks to sell at $7.99. the cost to the store is $5.29. what is the markup rate on a paperback book, based on its cost?

The formula for the lateral area of a right cone is la = rs, where r is the radius of the base and s is the slant height of the cone. which are equivalent equations?