An Ontario lottery has the following structure, the first person drawn from the names wins $15 000. Each subsequent person drawn wins $150 less than the person before. The last person drawn wins $6000. a) Write the first four terms of the sequence that represents the winnings.
b) Determine a and d for the sequence.
c) Determine an explicit formula for the general term.

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.