Find the number of ways to distribute k different objects
inton different boxes, so that no box is empty.

Anumber cube is rolled two times in a row. find the probability it will land on 2 on the first roll and a number greater then 4 on the second roll

Rhombus adef is inscribed into a triangle abc so that they share angle a and the vertex e lies on the side bc . what is the length of the side of the rhombus if ab=c, and ac=b.

In the diagram below de and ed are tangent to 0 which expression gives the measure of def