A Liar's Weakness

Computer Science Level 3

Jerry likes to lie, he lies every day of the week except for one day. One day, he said "I lie on Mondays and Tuesdays." The following day, he said "Today is one of the following days, Sunday, Saturday, or Thursday". On the next day he said "I only lie on Fridays and Wednesdays!". On what day he's telling the truth?

Thursday Friday Tuesday Monday

Jerry Courenelis by Jerry Courenelis , 20, Indonesia

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Jerry Courenelis
May 25, 2014

Jerry's 1st and 3rd statements can't be both true, or both false, because he only tells the truth on one day every week. Given by the number of possibilities :

If he doesn't lie on Mondays.. The third statement is true, although, that means the second statement is also true. So he'd be telling the truth on 2 days, in which is not possible.

If he doesn't lie on Tuesdays.. The third statement is true, and his words on Mondays is false. That way, there is only one day that he tells the truth. Therefore, he must be telling the truth on Tuesdays.

1 Helpful 0 Interesting 0 Brilliant 0 Confused

I think the third statement is confusing. It seemed to be saying, "I lie only on Fridays and Wednesdays". Clearly false based on the problem statement.

Instead you seem to be reading it as, "I lie on both Fridays and Wednesdays".

So I'm not sure what the word "only" meant here. Probably I'm confused. I certainly feel confused.

Steven Perkins - 7 years ago

Log in to reply

That's right only makes the statement false. Will puzzler decode the meaning?

Shyambhu Mukherjee - 5 years, 6 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...