An item is regularly priced $40 at . It is on sale for 20% off the regular price. How much (in dollars) is discounted from the regular price?

Three times the sum of a number and seven is negative thirty-six. what is the number?

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

Joe has a rectangular chicken coop. the length of the coop is 4 feet less than twice the width. the area of the chicken coop is 510 square feet. what is the length of the chicken coup?