The ratio of the number of ducks in Farm X to the number of ducks in Farm Y was 4 : 7. There were 63 more ducks in Farm Y than in Farm X. When 9 ducks escaped from Farm Y, the farmer in Farm Y bought another 15 ducks. What was the new ratio of the number of ducks in Farm X to the number of ducks in Farm Y in the end? Give your answer in the simplest form.
| |
Farm X |
Farm Y |
| Before |
4 u |
7 u |
| Change 1 |
|
- 9 |
| Change 2 |
|
+ 15 |
| After |
4 u |
7 u + 6 |
Number of more ducks in Farm Y than Farm X
= 7 u - 4 u
= 3 u
3 u = 63
1 u = 63 ÷ 3 = 21
Number of ducks in Farm X
= 4 u
= 21 x 4
= 84
Number of ducks in Farm Y
= 7 u
= 21 x 7
= 147
New number of ducks in Farm Y
= 7 u + 6
= 147 + 6
= 153
Farm X : Farm Y
84 : 153
(÷ 3)28 : 51
Answer(s): 28 : 51
