Justin had
29 as many stamps as Irene. After Justin bought another 130 stamps, he had 10 less stamps than Irene. How many stamps did Justin have at first?
| |
Justin |
Irene |
| Before |
2 u |
9 u |
| Change |
+ 130 |
|
| After |
2 u + 130 |
9 u |
Irene had 10 more stamps than Justin in the end. So, if Justin had another 10 stamps, he would have the same number of stamps as Irene.
9 u = 2 u + 130 + 10
9 u - 2 u = 130 + 10
7 u = 140
1 u = 140 ÷ 7 = 20
Number of stamps that Justin had at first
= 2 u
= 2 x 20
= 40
Answer: 40
