Maths Week Challenge 2 – King Rumbo

13 Oct 2015

It’s Maths Week! We’ve partnered up with University College Cork – currently celebrating the bicentenary of the birth of noted mathematician George Boole – to bring you fun and interesting maths challenges every day this week.

Tuesday’s Maths Week Challenge

King Rumbo likes to make crazy rules for his people. For example, in Rumbo’s country, everybody must wear a letter on their front and a number on their back.

A new rule states, “If you wear 7 on one side, then you must wear an A on the other side”.

King Rumbo sees seven people walking in various directions on the street.

They’re wearing an A, a 7, a B, a 6, a C, a 5 and an A, respectively.

He’d like to call some of them and check if they cheated on his new rule. However, for security reasons, the king’s council has forbidden the king from checking on more than three people at once.

Which three people should the king call?

Today’s Maths Week Challenge comes courtesy of Dr Anca Mustata, UCC School of Mathematical Science and Maths Circles Ireland.

Make sure to check back in tomorrow for the solution to today’s Challenge.

Update: For the solution to Maths Week Challenge 2, click here.

Solution to Monday’s challenge

In the West wing, Joe took the room on the top floor, Owen took the ground floor, and Mark took the basement. In the North wing, Kevin took the top room, Harry the ground floor and John the basement. Tom took the top floor in the East wing, Michael took the ground floor, and Denis took the basement.

Main image via Shutterstock