A hard math riddle
Seven friends meet, and each one shakes hands with every other friend once. How many handshakes are there?
💡 Need a hint?
The first friend shakes 6 hands, the next one 5 new hands.
Show the answer
21
Also accepted: twenty-one.
Think it through before you peek. Stuck? Read the riddle out loud: many riddles hide the answer in a word with two meanings.
3 more riddles like this
- A dad is 30 years older than his son. In 5 years he will be 3 times as old as his son. How old is the son now? See the answer →
- Each hand has 5 fingers, counting the thumb. How many fingers are there on 10 hands? See the answer →
- A farmer has 17 sheep. All but 9 run away. How many are left? See the answer →
Frequently asked questions
What is the answer to the riddle "Seven friends meet, and each one shakes hands with every other friend once. How many handshakes are there?"
The answer is 21. The first friend shakes 6 hands, the next one 5 new hands.
Is this riddle hard?
It is rated hard. Many adults need the hint, so do not worry if it takes a while.
Where can I find more riddles like this?
This riddle is in the math riddles and puzzles, logic puzzles, riddles for adults, and hard riddles lists on Quiz Zoomies, each with hints and hidden answers.
More riddle lists
Logic Puzzles
Logic puzzles with answers: reason it out, no special knowledge.Riddles for Adults
Riddles for adults: wordplay, logic and number tricks with answers.Hard Riddles
Hard riddles with hints and answers for riddle experts.All Riddles A to Z
Every riddle on its own page, with a hint, the answer and three more like it.
A new quiz every day on YouTube
Flags, capitals, trivia, riddles and brain teasers. Subscribe to Quiz Zoomies and test yourself with a new quiz video every day, plus Shorts in between.