Question

Each of the students of G4 group shook hands with everyone else standing in that group exactly once, how many handshakes were there altogether? a) 15 b) 30 c) 105 d) 210​

Answer 1

$\underline{\bf\purple{\dag}\:\mathfrak{Answer }}$

ɪɴ ᴛʜᴀᴛ ᴄᴀsᴇ ɢᴜᴇsᴛ 1 ᴡɪʟʟ sʜᴀᴋé ʜᴀɴᴅs ᴡɪᴛʜ 5 ᴏᴛʜᴇʀs (ɢᴜᴇsᴛ 2 ᴛᴏ 6)

ɢᴜᴇsᴛ 2 ᴡɪʟʟ sʜᴀᴋᴇ ʜᴀɴᴅs ᴡɪᴛʜ 4 ᴏᴛʜᴇʀs (ʀᴇᴍᴇᴍʙᴇʀ sʜᴇ's ᴀʟʀᴇᴀᴅʏ sʜᴀᴋᴇń ʜᴀɴᴅs ᴡɪᴛʜ ɢᴜᴇsᴛ 1).

ɢᴜᴇsᴛ 3 ᴡɪʟʟ sʜᴀᴋᴇ ʜᴀɴᴅs ᴡɪᴛʜ 3 ᴏᴛʜᴇʀs (ʜᴀᴠɪɴɢ ᴀʟʀᴇᴀᴅʏ sʜᴀᴋé ʜᴀɴᴅs ᴡɪᴛʜ ɢᴜᴇsᴛ 1 ᴀɴᴅ 2)

ᴀɴᴅ sᴏ ᴏɴ

ᴡᴇ ᴇɴᴅ ᴜᴘ ᴡɪᴛʜ 5+4+3+2+1 ʜᴀɴᴅsʜᴀᴋᴇś ᴏʀ 15 ʜᴀɴᴅsʜᴀᴋᴇś ɪɴ ᴀʟʟ!

sᴏ 15 ɪs ᴛʜᴇ ᴀɴsᴡᴇʀ

Answer 2

EVERYONE SHAKES HAND WITH EVERYONE ONCE

GIVEN :

There are 6 people

Guest 1 will shake hands with FIVE people

Guest 2 will shake hands with FOUR people as he has already shook hands with Guest 1

Guest 3 will shake hands with THREE people as he had already shaken hands with Guest 1 and 2

Guest 4 will shake hands with TWO people

Guest 5 will shake hands with ONE person.

Therefore the total number of handshakes will be 5+4+3+2+1=15

There are 15 handshakes in all.

#SPJ2