Question

Farmer freddy keeps his cows and ducks in the barn. If there are 13 animals in the barn & altogether they have 34 legs how many cows & ducks does he have?

Answer 1

let the number of cows be X
       the number of ducks be Y

we know that there are 13 animals including cows and ducks

so X+Y= 13

cows have 4 legs and ducks have 2 legs and totally we have 34 legs, from this we can create another equation

4*X + 2*Y= 34

now we have two equations

- X+Y= 13
 -4*X + 2*Y= 34

equalising the first  equation , we can arrange them like given

4*X+ 2*Y= 34
2*X+ 2*Y= 26

subtracting second equation from first we will get

......2*X = 8
        X= 4 

X+Y= 13
   Y= 13-4
     =9 

4 COWS HAVE 16 LEGS AND 9 DUCKS HAVE 18 LEGS . THAT MEANS THERE ARE TOTAL 13 ANIMALS AND 34 LEGS