One Of Them Has To Be Right!

Logic Level 2

A, B, C, D and E are Boolean variables, meaning that they are either true or false. It is known that A and E are both true.

If exactly one of the following pairs of variables are both true, which pair is it?

C and D B and D E and B A and B C and E

View wiki
Anthony Ling by Anthony Ling , 24, USA

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

Anthony Ling
May 5, 2016

Relevant wiki: Truth-Tellers and Liars

Here's what we know:

  • A : True
  • B : False (" E & B " & " A & B " can't be both the correct answer)
  • C : Unknown
  • D : Unknown
  • E : True

With the process of elimination, we can take off " B & D " since we know that B is false. That leaves " C & D " and " E & C ". Since we know that there must be a correct answer, C has to be true, and since E was already true, " E & C " must be the correct answer ( D is false).

10 Helpful 0 Interesting 0 Brilliant 0 Confused

how did you get B as false?? i didn't get it properly

Abhijit Das - 5 years, 1 month ago

Log in to reply

So from the problem we know that A and E are true. The only options for B on the answer thing is A and B or E and B. As there is only one answer for the question, It is impossible to rule which one is true. This means it's false.

Live long and prosper, Stronak the Vulcan

Stronak The Vuclan - 5 years, 1 month ago

Oh nice! Thanks for fixing the previous version.

I've edited the problem to clarify what you're asking for.

Calvin Lin Staff - 5 years, 1 month ago

Nice problem and solution. @Anthony Ling

Thanks for sharing. Keep it up.

Sandeep Bhardwaj - 5 years, 1 month ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...