MemberOct 9, 2011

## Puzzle Master - Next Puzzle - Tea or Coffee after Dinner?

X,Y and Z often eat dinner out.

1. Each orders either coffee or tea after dinner.
2. If X orders coffee, then Y orders the drink that Z orders.
3. If Y orders coffee, the X orders the drink that Z doesn't order.
4. If Z orders tea, then X orders the drink that Y orders.

Who do you know always orders the same drink after dinner?
Howdy guest!
Dear guest, you must be logged-in to participate on CrazyEngineers. We would love to have you as a member of our community. Consider creating an account or login.
Replies
• MemberOct 10, 2011

I think its X.
Are you sure? This action cannot be undone.
• MemberOct 10, 2011

Statements 2, 3 and 4 cannot be simultaneously true because they are mutually exclusive logically. The puzzle makes sense only if 2, 3 or 4 are considered individually. That is, the result depends on who orders first.

X orders coffee first, subsequently both Z and Y order either coffee or tea depending on Z's choice. If X orders tea first, then Y and Z may order either.
This means we have X-coffee or tea, Y- tea or coffee and Z tea or coffee.
tea. Z now orders coffee or tea while X orders Tea or coffee Y orders coffee first. If Z now orders coffee then X orders tea, else Z orders tea and X orders coffee. Y orders c
We have Y-coffee or tea, Z- coffee or tea and X-tea or coffee.

Z orders tea first, then Y orders tea or coffee and X orders tea or coffee. If Z orders coffee first then Y orders tea or coffee and X orders tea or coffee.
We have Z - coffee or tea, Y-coffee or tea and X -coffee or tea.

This means that they all may order tea or coffee. No one has only the same drink.

There seems to be no unique solution.
Are you sure? This action cannot be undone.
• MemberOct 10, 2011

There are 6 cases.

X Y Z
I coffee coffee coffee
II coffee tea tea
III tea coffee coffee
IV tea tea tea
V tea coffee tea
VI tea tea coffee

Then, from 3rd Point, Cases I and V are eliminated and, from 4th Point, Cases II and V are eliminated.

So X always orders the same drink (tea) after dinner.
Are you sure? This action cannot be undone.
• MemberOct 11, 2011

born_star16
There are 6 cases.

X Y Z
I coffee coffee coffee
II coffee tea tea
III tea coffee coffee
IV tea tea tea
V tea coffee tea
VI tea tea coffee

Then, from 3rd Point, Cases I and V are eliminated and, from 4th Point, Cases II and V are eliminated.

So X always orders the same drink (tea) after dinner.
Yes the logic and answer is correct.
Are you sure? This action cannot be undone.