You have two switches: A and B. They can be on or off. They both start off.

The only rule is you can't switch the same switch twice.

You start by switching A on.

After 20 minutes your mom calls, and after the call you don't remember what you did last.

How will you know which switch to switch next?

Edited December 29, 20187 yr by QuantumT

Because it's in the down position?

Solution to those who don't want to bother solving it:

Spoiler

If both switches are off or on, you choose A.

If one is off and one is on, you choose B.

 

That only works if you specify more information at the beginning.

8 minutes ago, studiot said:

That only works if you specify more information at the beginning.

You mean like this?

On 29/12/2018 at 1:09 AM, QuantumT said:

You have two switches: A and B. They can be on or off. They both start off.

The only rule is you can't switch the same switch twice.

You start by switching A on.

 

13 minutes ago, studiot said:

I mean no disrespect, but I can't tell if you're being condescending, or if you missed the info at first glance?

1 hour ago, QuantumT said:

I mean no disrespect, but I can't tell if you're being condescending, or if you missed the info at first glance?

Oops you are right.

I didn't read it properly and missed the bit where you said both were off to begin with.

So the smiley was to say "yup that's one way to do it."

Let that be a lesson to those who are still condemned to take exams.

Read the Frigging Question.

My apologies. +1

7 minutes ago, studiot said:

So the smiley was to say "yup that's one way to do it."

Thanks for the clarification. Very much appreciated!