Cathy used
57 of her grey stickers and
37 of her black stickers to decorate her diary. In the end, she had an equal number of grey stickers and black stickers left. Given that Cathy had a total of 252 grey and black stickers at first, how many black stickers did she use to decorate the diary?
|
Grey stickers |
Black stickers |
Before |
7x2 = 14 u |
7x1 = 7 u |
Change |
- 5x2 = - 10 u |
- 3x1 = - 3 u |
After |
2x2 = 4 u |
4x1 = 4 u |
The number of grey stickers and black stickers in the end is the same. Make the number of grey stickers and black stickers in the end the same. LCM of 2 and 4 is 4.
Total number of stickers that Cathy used to decorate the diary
= 14 u + 7 u
= 21 u
21 u = 252
1 u = 252 ÷ 21 = 12
Number of black stickers that Cathy used to decorate the diary
= 3 u
= 3 x 12
= 36
Answer(s): 36