John consistently saves 7/12
of his monthly salary. John's salary has recently been increased by $312.
As a result of the pay raise, John's monthly savings is now $1512. How much was John's salary before
the pay raise?

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.