Joanna's pay for working overtime varies jointly as the number of hours she works and her hourly pay rate. if her overtime pay is $103.44 when she works 8 hours at an hourly rate of $8.62, then find the number of hours worked when her overtime pay is $213.75 at an hourly rate of $9.50.

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.