Julie and Cathy had an equal number of stickers at first. Julie used
13 of her stickers and Cathy used
17 of her stickers. They used 30 stickers altogether. How many stickers did Cathy have in the end?
| |
Julie |
Cathy |
| Before |
3x7 =
21 u |
7x3 =
21 u |
| Change |
- 1x7 =
- 7 u |
- 1x3 =
- 3 u |
| After |
2x7 =
14 u |
6x3 =
18 u |
The number of stickers that Julie and Cathy each had at first is the same. Make the number of stickers that Julie and Cathy each had at first the same. LCM of 3 and 7 is 21.
Number of stickers that Julie and Cathy used
= 7 u + 3 u
= 10 u
10 u = 30
1 u = 30 ÷ 10 = 3
Number of stickers that Cathy had in the end
= 18 u
= 18 x 3
= 54
Answer(s): 54
