Answer:
The weight of 1 duck = 12 Kg and weight of 1 chicken is 10 Kg.
Explanation:
Let the weight of one duck = x
Let the weight of one chicken = y
The weight of 3 ducks and 4 chicken is 76 kg
----- (1)
The weight of 4 ducks and 3 chicken is 78 kg
------- (2)
Let us multiply equation (1) by 4 and equation (2) by 3
------ (3)
------ (4)
Subtracting (3) and (4) :
![\[7y=70\]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/tmolfpkb55w7azepjjhr4elrrdche0oamc.png)
![\[y=10\]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/48zuvt7junnjervab819vc7fh9toarda3t.png)
Substituting the value of y in (1):
![\[=>3x+ (4 * 10)=76\]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/cw76yzvahq32tr36leabd7umb16vhnksze.png)
![\[=>3x=76-40\]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/9o3wz06sdjmdzckmcbmzgx0elrjomsbqrw.png)
![\[=>x=12\]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/t6nhg6k2qoeyhca7tuucf8c80nfwnz4f00.png)
So the weight of 1 duck = 12 Kg and weight of 1 chicken is 10 Kg.