Owen had
25 as many buttons as Erika. After Owen bought another 20 buttons, he had 10 less buttons than Erika. How many buttons did Owen have at first?
|
Owen |
Erika |
Before |
2 u |
5 u |
Change |
+ 20 |
|
After |
2 u + 20 |
5 u |
Erika had 10 more buttons than Owen in the end. So, if Owen had another 10 buttons, he would have the same number of buttons as Erika.
5 u = 2 u + 20 + 10
5 u - 2 u = 20 + 10
3 u = 30
1 u = 30 ÷ 3 = 10
Number of buttons that Owen had at first
= 2 u
= 2 x 10
= 20
Answer: 20