A man bought 2 CD's and 3 books for $48 while shopping in the local bookstore. A woman shopping in the same store bought 4 CD's and 2
books and spent $60. Assume that each CD costs the same and also that
the cost of each book is the same. Which system of linear equations
below can be solved to find out the cost of a CD and a book? *

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.