Ivory used ²₅ of her black stickers and ³₇ of her yellow stickers to decorate her diary. In the end, she had an equal number of black stickers and yellow stickers left. Given that Ivory had a total of 287 black and yellow stickers at first, how many yellow stickers did she use to decorate the diary?

	Black stickers	Yellow stickers
Before	5x4 = 20 u	7x3 = 21 u
Change	- 2x4 = - 8 u	- 3x3 = - 9 u
After	3x4 = 12 u	4x3 = 12 u

The number of black stickers and yellow stickers in the end is the same.  Make the number of black stickers and yellow stickers in the end the same.  LCM of 3 and 4 is 12.

Total number of stickers that Ivory used to decorate the diary
= 20 u + 21 u
= 41 u

41 u = 287

1 u = 287 ÷ 41 = 7

Number of yellow stickers that Ivory used to decorate the diary
= 9 u
= 9 x 7
= 63

Answer(s): 63