Buffalo gives 4 liter milk, cow gives (1/2) liter milk and goat gives 1/4 liter milk. you have to get 20 liter milk by 20 animals.what is the number of cows?
Select the correct option:
A) 12 B) 13 C) 14 D) 15 E) 16
Assume number of respective animals are x,y,z.   x+y+z=20---(1) as the total number of animal has to be 20   Amt of milk will be 4x+(1/2)y+(1/4)z=20---(2)   Solving equation 1 and 2 we get   15x+y=60 ----(3)   Since buffalo gives 4litre and total milk is 20, x &lt; 5   But from eq 3, x cannot be more than 4;   Further if x=1 or 2; y&gt;20... Not possible, since total animal is 20   Thus, x=3, y=15, z=2   15cows   ANSWER:15
<result>D</result>
Buffalo gives 4 liter milk, cow gives (1/2) liter milk and goat gives 1/4 liter milk. you have to get 20 liter milk by 20 animals.what is the number of cows?