The ratio of Michael's stamps to Gavin's stamps at first was 2 : 5. After Michael gave Gavin 12 stamps, the ratio of Michael's stamps to Gavin's stamps is 1 : 4. What was the number of stamps they had altogether?
| |
Michael |
Gavin |
Total |
| Before |
2x5 =
10 u |
5x5 =
25 u
|
7x5 =
35 u |
| Change |
- 12 |
+ 12 |
|
| After |
1x7 =
7 u |
4x7 =
28 u |
5x7 =
35 u |
Number of stamps that Michael gave Gavin
= 10 u - 7 u
= 3 u
3 u = 12
1 u = 12 ÷ 3 = 4
Total number of stamps that they had
= 35 u
= 35 x 4
= 140
Answer(s): 140
