There are 28 persons present at a press conference. After the conference they all shake hands with each other. If 7 of them refuse to shake hands at all, then how many hands shakes will be there altogether?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e 210.
Given,
Number of persons = 28
Number of persons who refused to shake hands = 7
Therefore, number of persons who shaked their hands = 28 - 7 = 21
Now,
21 (21 - 1) ÷ 2
21 × 20 ÷ 2
21 × 10 = 210
Hence, option 4 is the correct answer.