If a farmer sells 5 of his chickens, his stock of feed will last for 4 more days than planned, but if he buys 10 more chickens, he will run out of feed 3 days earlier than planned. If no chickens are sold or bought, the farmer will be exactly on schedule. How many chickens does the farmer have? Choices:
A) 12	B) 24	C) 20	D) 55	E) 60
Say farmer has n chicken and he is good for d days.:-   We have 3 equations given in question:-   (n-5) * d+4 =(n+10) *(d-3) = n * d   Solving these: (You can solve 1st and 3rd and 2nd and 3rd together)   We get:   10d-3n=30   4n-5d =20   =&gt; n=20   Ans 20 it is!
<result>C</result>
If a farmer sells 5 of his chickens, his stock of feed will last for 4 more days than planned, but if he buys 10 more chickens, he will run out of feed 3 days earlier than planned. If no chickens are sold or bought, the farmer will be exactly on schedule. How many chickens does the farmer have?