In May, Fiona and Seth had stamps in the ratio 15 : 7. In June, each of them gave away the same number of stamps. Fiona then had thrice as many stamps as Seth.
- Find the ratio of the number of stamps Seth had in May to the number of stamps he had in June.
- Find the ratio of the total number of stamps both had in May to the total number of stamps both had in June.
| |
Fiona |
Seth |
Difference |
| Before |
15x1 =
15 u |
7x1 =
7 u |
8x1 =
8 u |
| Change |
- 3 u |
- 3 u |
|
| After |
3x4 =
12 u |
1x4 =
4 u |
2x4 =
8 u |
(a)
Since Fiona and Seth gave away the same number of stamps, the difference in the number of stamps between Fiona and Seth at first and in the end remains the same.
Make the difference in the number of stamps at first and in the end the same. LCM of 8 and 2 is 8.
Seth's stamps in May : Seth's stamps in June
7 : 4
(b)
Total number of stamps in May
= 15 u + 7 u
= 22 u
Total number of stamps in June
= 12 u + 4 u
= 16 u
Total stamps in May : Total stamps in June
22 : 16
(÷2)11 : 8
Answer(s): (a) 7 : 4; (b) 11 : 8
