Shiyun had 30 more buttons than Joelle. After Joelle gave away
13 of her buttons, Shiyun had thrice as many buttons as Joelle. How many buttons did Joelle have at first?
| |
Shiyun |
Joelle |
Comparing Shiyun and
Joelle at first |
30 more |
|
| Before |
6 u |
3 u |
| Change |
|
- 1 u |
| After |
6 u |
2 u |
Comparing Shiyun and
Joelle in the end |
3x2 =
6 u |
1x2 =
2 u |
Number of buttons that Joelle had in the end is repeated. Make the number of buttons that Joelle had in the end the same. LCM of 1 and 2 is 2.
Number of buttons that Shiyun had at first = 6 u
Number of buttons that Shiyun had more than Joelle at first
= 6 u - 3 u
= 3 u
3 u = 30
1 u = 30 ÷ 3 = 10
Number of buttons that Joelle had at first
= 3 u
= 3 x 10
= 30
Answer(s): 30
