Multiple choice general knowledge math & puzzles

It was Diane 's first day at school. The teacher suggested that it would be a good idea for each child to meet every other child in the class. The teacher said, "When you meet, please shake hands and introduce yourself by name." If there were 15 children in the class, how many total handshakes were there?

  1. 100

  2. 80

  3. 60

  4. 105

  5. 210
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The number of handshakes among 15 people is calculated using the combination formula n(n-1)/2. For 15 children, this is (15 * 14) / 2 = 105. The option 210 is incorrect because it counts each handshake twice (A shaking B and B shaking A).

Keep practicing — related questions