A mathematical question?

Question

A farmer has twenty animals including goat, baffelo and cows. He takes 40 kg milk from these animals daily. If one goat (z)give 0.25 kg milk, one baffelo(x) give 5 kg milk and cow(y) give 2kg milk in one time. can any body tell that how much animal of each kind he has?
Actually I made two equations but I need third equation to solve it.
equation 1 is 5x+2y+0.25z=40
equation 2 is x+y+z=20
x , y or z cannot be equal to 0

Answer 1

Dear friend, 1st of all these kind of questions are based on dealing with +ve integers as the number of the animals must be +ve integers
so
5x+2y+(1/4)z=40 , x=20-y-z
5(20-y-z)+2y+(1/4)z=40
100-5y-5z+2y+(1/4)z=40
60=3y+(19/4)z -->/3
20=y+(19/12)z
now u will notice that (19/12)z must be integer
so z must be a 12n,(i.e. 12,24,36,...)and as the number of the animals are 20 so if z>12 so the x & y will be -ve(wrong answer)
so the only possible result is z=12 and so 20=y+(19/12)12=y+19
so y=1
x=20-y-z=20-12-1=20-13=7
so x=7,y=1,z=12

Answer 2

G + B + C = 20 . . . equation 1
.25 G + 5 B + 2 C = No? . . . . .
.25(8) + 5(8) + 2 (6) = 54 . . . not this one
.25(8) + 5(6) + 2 (6) = 44 . . . not this one
.25(8) + 5(6) + 2 (5) = 42 . . . not this one
.25(8) + 5(6) + 2 (4) = 40 . . . this is OK
answer: there are
8 Goats
6 Buffalos
4 Cows

Answer 3

12 goats
1 cow
7 buffaloes

12 x .25 = 3
1 x 2 = 2
7 x 5 = 35

20 animals and 40 units of milk

Answer 4

equation 1 is 5x+2y+0.25z=40
equation 2 is x+y+z=20
From eq.2 z = 20 – x – y ----------- eq 3
From eq.1 20x + 8y + z = 160 -------- (0.25 = 1/4 multiply eq. 1 by 4)
20x + 8y + z = 140
20 x + 8y + 20 – x – y = 160 ------------- putting value of z (eq 3)
19 x + 7 y = 140
x = 140 – 7y /10
Let y = 1 then x = 140 – 7/19
x = 7
X = 7, y = 1, so z = 12