Question

A box contains 15 apples. How many different selections of 3 apples can be made sco as to include a particular apple?

Answer 1

Answer:

Total number of different selections  = 455

Explanation:

Number of selections from n objects if we select r things $=^nC_r$            

Here we need to find number off selections of 3 apples from 15 apples.

Number off selections of 3 apples from 15 apples

                    $=^{15}C_3=\frac{15\times 14\times 13}{1\times 2\times 3}=455$

Total number of different selections  = 455