The ratio of the number of chickens in Farm M to the number of chickens in Farm N was 4 : 7. There were 63 fewer chickens in Farm M than in Farm N. When 6 chickens escaped from Farm N, the farmer in Farm N bought another 18 chickens. What was the new ratio of the number of chickens in Farm M to the number of chickens in Farm N in the end? Give your answer in the simplest form.

	Farm M	Farm N
Before	4 u	7 u
Change 1		- 6
Change 2		+ 18
After	4 u	7 u + 12

Number of fewer chickens in Farm M than Farm N
= 7 u - 4 u
= 3 u

3 u = 63

1 u = 63 ÷ 3 = 21

Number of chickens in Farm M
= 4 u
= 21 x 4
= 84

Number of chickens in Farm N
= 7 u
= 21 x 7
= 147

New number of chickens in Farm N
= 7 u + 12
= 147 + 12
= 159

Farm M : Farm N
84 : 159 _{(÷ 3)}
28 : 53

Answer(s): 28 : 53