### 14 Divisors

What is the smallest number with exactly 14 divisors?

### Summing Consecutive Numbers

Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?

### Rule of Three

If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?

# Weekly Problem 20 - 2010

##### Stage: 3 Short Challenge Level:

The diagram show the net of a regular octohedron.

In a Magic Octahedron, the four numbers on the faces that meet at a vertex add up to make the same total for every vertex. If the letters $F, G, H, J$ and $K$ are replaced with the numbers $2, 4, 6, 7$ and $8$, in some order, to make a Magic Octohedron, what is the value of $G + J$?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.

View the previous week's solution