In January, Tammy and Luis had coins in the ratio 11 : 7. In February, each of them gave away the same number of coins. Tammy then had thrice as many coins as Luis.
- Find the ratio of the number of coins Luis had in January to the number of coins he had in February.
- Find the ratio of the total number of coins both had in January to the total number of coins both had in February.
| |
Tammy |
Luis |
Difference |
| Before |
11x1 =
11 u |
7x1 =
7 u |
4x1 =
4 u |
| Change |
- 5 u |
- 5 u |
|
| After |
3x2 =
6 u |
1x2 =
2 u |
2x2 =
4 u |
(a)
Since Tammy and Luis gave away the same number of coins, the difference in the number of coins between Tammy and Luis at first and in the end remains the same.
Make the difference in the number of coins at first and in the end the same. LCM of 4 and 2 is 4.
Luis's coins in January : Luis's coins in February
7 : 2
(b)
Total number of coins in January
= 11 u + 7 u
= 18 u
Total number of coins in February
= 6 u + 2 u
= 8 u
Total coins in January : Total coins in February
18 : 8
(÷2)9 : 4
Answer(s): (a) 7 : 2; (b) 9 : 4
