White shapes and black shapes are used in a game.
Some of the shapes are circles.
All other shapes are squares.
The ratio of the number of white shapes to the number of black shapes is 7:3
The ratio of the number of white circles to the number of white squares is 2:7
The ratio of the number of black circles to the number of black squares is 1:2

Work out what fraction of all the shapes are circles.
Give your answer in its simplest form.

(Hint: Fractions can be written in the form a/b. eg [tex]\frac{5}{28}[/tex] would be written as 5/28