The ratio of the number of ducks in Farm C to the number of ducks in Farm D was 4 : 9. There were 40 fewer ducks in Farm C than in Farm D. When 10 ducks escaped from Farm D, the farmer in Farm D bought another 16 ducks. What was the new ratio of the number of ducks in Farm C to the number of ducks in Farm D in the end? Give your answer in the simplest form.
|
Farm C |
Farm D |
Before |
4 u |
9 u |
Change 1 |
|
- 10 |
Change 2 |
|
+ 16 |
After |
4 u |
9 u + 6 |
Number of fewer ducks in Farm C than Farm D
= 9 u - 4 u
= 5 u
5 u = 40
1 u = 40 ÷ 5 = 8
Number of ducks in Farm C
= 4 u
= 8 x 4
= 32
Number of ducks in Farm D
= 9 u
= 8 x 9
= 72
New number of ducks in Farm D
= 9 u + 6
= 72 + 6
= 78
Farm C : Farm D
32 : 78
(÷ 2)16 : 39
Answer(s): 16 : 39