Assignment:
Q1. The integers 1 through 25 are arranged in a 5 x 5 array (we use each number from 1 to 25 exactly once). All that matters is which numbers are in each column and how they are arranged in the columns. It does not matter in what order the columns appear. (The two arrays should be considered to be the same.) How many different such arrays can be formed?
Q2. Twenty people are to be divided into two teams with ten players on each team. In how many ways can this be done?
Provide complete and step by step solution for the question and show calculations and use formulas.