- Rachel has some first class and some second class stamps.
The ratio of the number of first dass to the number of second class stamps is 3:4
Rachel has 18 first class stamps.
(a How many second class stamps do es Rachel have?
b) How many stamps do es Rachel have in total?

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.