Primeless Road: Upper Primary Mathematics Competition Question

Primeless Road is a rather peculiar road. All the odd numbered houses are on one side of the road, and all the even ones are on the other side, both sides starting with the lowest number. Nothing very strange with that! However, none of the house numbers is a prime number.

Assuming each house has exactly one other house directly opposite, what is the number of the house opposite number 20?

You can write your answer and discuss the question in the Comments section below.

Level: Upper Primary (Green)


You can receive these questions directly to your email box or read them in an RSS reader. Subscribe using the links on the right.

Don’t forget to follow Gifted Mathematics on Google+, Facebook or Twitter. You may add your own interesting questions on our Google+ Community and Facebook..

You can also subscribe to our Bookmarks on StumbleUpon and Pinterest. Many resources never make it onto the pages of Gifted Mathematics but are stored in these bookmarking websites to share with you.