Marion had 15 more buttons than Sarah. After Sarah gave away
14 of her buttons, Marion had thrice as many buttons as Sarah. How many buttons did Sarah have at first?
| |
Marion |
Sarah |
Comparing Marion and
Sarah at first |
15 more |
|
| Before |
9 u |
4 u |
| Change |
|
- 1 u |
| After |
9 u |
3 u |
Comparing Marion and
Sarah in the end |
3x3 =
9 u |
1x3 =
3 u |
Number of buttons that Sarah had in the end is repeated. Make the number of buttons that Sarah had in the end the same. LCM of 1 and 3 is 3.
Number of buttons that Marion had at first = 9 u
Number of buttons that Marion had more than Sarah at first
= 9 u - 4 u
= 5 u
5 u = 15
1 u = 15 ÷ 5 = 3
Number of buttons that Sarah had at first
= 4 u
= 4 x 3
= 12
Answer(s): 12
