Find the cost price when,
(a) Selling price = Rs 725 and 15% gain

Ihonestly don’t understand this at all

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex