### Overturning Fracsum

Solve the system of equations to find the values of x, y and z: xy/(x+y)=1/2, yz/(y+z)=1/3, zx/(z+x)=1/7

### Building Tetrahedra

Can you make a tetrahedron whose faces all have the same perimeter?

### Rudolff's Problem

A group of 20 people pay a total of £20 to see an exhibition. The admission price is £3 for men, £2 for women and 50p for children. How many men, women and children are there in the group?

# What's it Worth?

##### Age 11 to 16 Challenge Level:

Each symbol has a numerical value. The total for the symbols is written at the end of each row and column.

Can you find the missing total that should go where the question mark has been put?

There's a lot of information in the grid, so you will need to make some choices about what to focus on first. Click below to see some images that draw your attention to particular parts of the grid.

What can you deduce from each image?

Image 1

Image 2

Image 3

Image 4

Image 5

Image 6

Can you find any other ways of solving the problem?

You can apply these strategies to similar problems.
Fruity Totals can be used to generate lots of different examples.