White shapes and black shapes are used in a game.
some of the shapes are circles.
all of the other shapes are squares
the ratio of the number of white shapes to the black shapes is 3: 7
the ratio of the number of white circles to the number of white squeres is 4: 5 the ratio of the number of black circles to the number of black squesres is 2: 5 work out what fraction of all the shapes are circles