If 40 sheep eat 40 bags of grass in 40 days. In how many days one sheep will eat one bag of grass? Choose the correct choice from the following answers:
A) 1
B) 20
C) 40
D) 80
E) 70
Explanation :   Let the required number of days be x.   Less sheep, More days (Indirect Proportion)   Less bags, Less days (Direct Proportion)   Sheep 1 : 40 :: 40 : x   Bags 40 : 1   1 x 40 x x = 40 x 1 x 40   x = 40.   Answer : 40
<result>C</result>
If 40 sheep eat 40 bags of grass in 40 days. In how many days one sheep will eat one bag of grass?