Sabrina and Betty have some stamps. If Sabrina gives 37 stamps to Betty, Betty will have 4 times the number of stamps as Sabrina. If Betty gives 5 stamps to Sabrina, Sabrina will have
25 as many stamps as Betty. How many stamps does Sabrina have at first?
| |
Case 1 |
Case 2 |
| |
Sabrina |
Betty |
Sabrina |
Betty |
| Before |
7 u + 37 |
28 u - 37 |
10 u - 5 |
25 u + 5 |
| Change |
- 37 |
+ 37 |
+ 5 |
- 5 |
| After |
1x7 =
7 u |
4x7 =
28 u |
2x5 =
10 u |
5x5 =
25 u |
The total number of stamps in both cases remains unchanged. Make the total number of stamps in both cases the same. LCM of 5 and 7 is 35.
Number of stamps that Sabrina had at first is the same in both cases.
10 u - 5 = 7 u + 37
10 u - 7 u = 37 + 5
3 u = 42
1 u = 14
Number of stamps that Sabrina had at first
= 7 u + 37
= 7 x 14 + 37
= 98 + 37
= 135
Answer(s): 135
