Question

How many ways can Mrs. Sullivan choose two

students from 27 to help put away calculators at
the end of class?

Answer 1

In 371 ways Mrs. Sullivan choose two students from 27 to help put away calculators at the end of class

Explanation:

let us assume that Mrs.Sullivan wants to choose 2 students from a group of 27 students

So ,in the first choice we have 27 students

In the second choice we have 26 choices

So Mrs.Sullivan has = 27 × 26 = 702 ways

But each group repeated twice,in order to avoid that we will divide the answer by 2

so we will write

= 702 ÷ 2 = 351 ways

This method of calculation is called Combination