How many different teams containing 5 members each can be formed from a group of 9 players

Aswimming pool had 2.5 million liters of water in it. some water evaporated, and then the pool only had 22 million liters of water in it. what percent of the water evaporated?

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

Prove that (x-2)is factor of p (x)=2x³-3x²-17x+30