In a depot there is oil stored in two identical barrels. One barrel is full, and the other is filled half way. Their weights are 86 and 53 pounds. How many pounds are two full barrels heavier than one empty barrel?

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.