Which colour is it then?

Logic Level 1

Mr. Robin asks his 5 students whether they studied maths yesterday.

White: "No one studied maths yesterday."
Brown: "1 person studied maths yesterday."
Gray: "2 people studied maths yesterday."
Blue: "3 people studied maths yesterday."
Black: "4 people studied maths yesterday."

Mr. Robin knows that only those who studied would be telling the truth and those who didn't would be lying. Who is telling the truth?

Black Gray Blue Brown White

3 solutions

Brock Brown
Mar 29, 2015

Those who study are telling the truth.

Every student's answer is different; Therefore, only 1 of them is telling the truth and only 1 person studied. Brown said only 1 person studied, so $\boxed{Brown}$ is the only one who studied.

That's right, it was $\boxed{me}$ the whole time. :P

Eduardo Neo
Jan 8, 2016

Perhaps you can add the word "Only" before each student statement, because without it, it seems that there might be more possible true options (e.g. both Brown and Grey were telling the truth, because since two students studied, you could say that one student did study).

You're right!

Claudio Augusto Rolim - 4 years, 8 months ago

Good point, Mr. Neo!

mash religion - 3 years, 6 months ago

Figel Ilham
Apr 4, 2015

I think the reason is that from all five students, only one is the truth, else lied. When we say nobody studies and it is the truth, it contradicts what Mr. Robin's thinking. For more than one, they must be lying since we know only one answer is correct and if there are more than one studies, there must be more than one who tell the truth. Thus there must be only one who studied!

That's what I thought, so Brown said 1 person studied, so, "that person" must be him/her!!!!! +, good explaining! ( even though I already got it).

mash religion - 3 years, 6 months ago

Which colour is it then?

3 solutions

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