Irene used ²₇ of her grey stickers and ²₅ of her brown stickers to decorate her diary. In the end, she had an equal number of grey stickers and brown stickers left. Given that Irene had a total of 506 grey and brown stickers at first, how many brown stickers did she use to decorate the diary?

	Grey stickers	Brown stickers
Before	7x3 = 21 u	5x5 = 25 u
Change	- 2x3 = - 6 u	- 2x5 = - 10 u
After	5x3 = 15 u	3x5 = 15 u

The number of grey stickers and brown stickers in the end is the same.  Make the number of grey stickers and brown stickers in the end the same.  LCM of 5 and 3 is 15.

Total number of stickers that Irene used to decorate the diary
= 21 u + 25 u
= 46 u

46 u = 506

1 u = 506 ÷ 46 = 11

Number of brown stickers that Irene used to decorate the diary
= 10 u
= 10 x 11
= 110

Answer(s): 110