Question

BRAIN TEASER!

Daniel and Isabel invited three couples for dinner. When they meet, not everyone is shaking hands with everyone. Later that evening Daniel asks, who shook how many hands. Although nobody shook the hand of his or her own partner, and nobody shook the hand of a person more than once, everyone is naming a different amount of handshakes. How many hands shook Isabel?

◆ Proper explanation needed.

Answer 1

7 hands would have shook Isabel.

6 hands of the couples and 1 hand of Daniel himself (Because Daniel and Isabel are not given to be couple or partners!)

Answer 2

Answer:

Let's assume that couples are-

A&A+

B&B+

C&C+

Let's also assume that that

A- Shakes 6 hands

A+- Shakes 0 hands

[Refer attachment]

The 1st diagram shows that A shakes B, B+, C, C+, D and I's hands

And A+ shakes no hands

For B and B+

Let's assume

B- Shakes 5 hands

B+- Shakes 1 hand

B shakes A, C, C+, D, I's hands

The second diagram shows this

And B shakes A's hand

And lastly

C- Shakes 4 hands

C+- Shakes 2 hands

C shakes B, A, D and I's hands

C+ shakes B+ and A's hands

And in total I's hand was shaken by A, B and C

Therefore Isabel shook 3 hands

Step-by-step explanation:

Also with the diagrams we see that no person, shakes another person's hand twice