Peter had
710 as many buttons as Yen. After Peter gave away 21 buttons, he had 78 less buttons than Yen. How many buttons did Yen have?
| |
Peter |
Yen |
| Before |
7 u |
10 u |
| Change |
- 21 |
|
| After |
7 u - 21 |
10 u |
Yen had 78 more buttons than Peter in the end. So, if Peter had another 78 buttons, he would have the same number of buttons as Yen.
10 u = 7 u - 21 + 78
10 u - 7 u = 78 - 21
3 u = 57
1 u = 57 ÷ 3 = 19
Number of buttons that Yen had at first
= 10 u
= 10 x 19
= 190
Answer: 190
