The ratio of the number of chickens in Farm Y to the number of chickens in Farm Z was 4 : 9. There were 65 fewer chickens in Farm Y than in Farm Z. When 12 chickens escaped from Farm Z, the farmer in Farm Z bought another 19 chickens. What was the new ratio of the number of chickens in Farm Y to the number of chickens in Farm Z in the end? Give your answer in the simplest form.

	Farm Y	Farm Z
Before	4 u	9 u
Change 1		- 12
Change 2		+ 19
After	4 u	9 u + 7

Number of fewer chickens in Farm Y than Farm Z
= 9 u - 4 u
= 5 u

5 u = 65

1 u = 65 ÷ 5 = 13

Number of chickens in Farm Y
= 4 u
= 13 x 4
= 52

Number of chickens in Farm Z
= 9 u
= 13 x 9
= 117

New number of chickens in Farm Z
= 9 u + 7
= 117 + 7
= 124

Farm Y : Farm Z
52 : 124 _{(÷ 4)}
13 : 31

Answer(s): 13 : 31