Jason bought some bookmarks and gave half to them to Kelvin. Kelvin
bought some stickers and gave half of them to Jason.
Then Jason gave 7 bookmarks to his brother and found that he had 1/9 as
many bookmarks as stickers left. Kelvin gave 12 stickers to his younger
brother and found that he had 1/6 as many bookmarks as stickers left.
(a) How many stickers did Kelvin have in the end?
(b) How many bookmarks did Jason buy?
Jason ==1/2B + 1/2S
Kelvin==1/2S + 1/2B
Jason ==[1/2B + 1/2S] - 7
[1/2B - 7] / [1/2S] ==1 / 9...................(1)
Kelvin==[1/2B] /[1/2S - 12] ==1/6....................(2), solve for B, S
(a) Kelvin had in the end==[1/2*324 - 12[==162 - 12 ==150 stickers.
(b)Jason bought ==50 Bookmarks.