Calvin bought 20 pencils at $0.45 each. how much change did he get from
a $10 bill?

Aparallel system functions whenever at least one of its components works. consider a parallel system of n components, and suppose each component works independently with probability 0.5. find the conditional probability that component n works given that the system is working

David is spreading mulch on a triangular area of his flower bed. the coordinates of the vertices of the area are (1, 3), (9, 3), and (4, 6). what is the area of the triangle if each square has an area of 3 square feet?

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?