Eric had
25 the number of stamps that Valen had at first. After Valen gave Eric 20 of his stamps, Eric had
45 the number of stamps that Valen had. How many stamps did Eric have at first?
|
Eric |
Valen |
Total |
Before |
2x9 = 18 u |
5x9 = 45 u |
7x9 = 63 u |
Change |
+ 10 u |
- 10 u |
|
After |
4x7 = 28 u |
5x7 = 35 u |
9x7 = 63 u |
The total number of stamps that Eric and Valen had at first and in the end remains unchanged. Make the total number of stamps the same. LCM of 7 and 9 is 63.
Number of stamps that Valen gave Eric
= 28 u - 18 u
= 10 u
10 u = 20
1 u = 20 ÷ 10 = 2
Number of stamps that Eric had at first
= 18 u
= 18 x 2
= 36
Answer(s): 36