State which of the following sets of ordered pairs represent a function. Set A: (5,2), (4,3), (3, 4), (2,5)
Set B: (-1,-6), (0, 2), (1, 2), (3,6)
Set C: (2, 1), (4, 2), (2, 3), (8,4)

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.