What is blank plus 1/2 to equal 4

Multiplying an even number of negative numbers gives an answer that is choose from:

Triangle xyz has vertices x(1,3), y(0,0)

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.