If Mary bought 12 of the Brand X batteries, how many of them lasted less than 15 hours? (Please show how you calculated this to get your answer

The hawaiian alphabet has 12 letters. how many permutations are posible for each number of letters?

The diagonals of a quadrilaretral intersect at (-1,4). one of the sides of the quadrilateral is bounded by (2,7) and (-3,5) determine the coordinates of the other side in order for the quadrilaretral to be a square.

Find two consexutive odd integers such that the sum of their square is 650