Question

There are 20 animals in a barn. Some are chickens and some are pigs. There are 56 legs in all. Let crepresent the number of chickens and let

p represent the number of pigs.
Which system of equations models this situation?
A 20c + 56p = 76
B) c + p = 56
2c + 4p = 20
C 2c + 4p = 20
4c + 2p = 56
D c + p = 20
2c + 4p = 56

Answer 1

D

Explanation:

If the total amount of chickens and pigs is 20, and the amount of legs (2 per chicken and 4 per pig), it's 56

We could set this up as a system of equation, and also set the variable as c = chickens and p = pig.

Since is a total amount of 20 for chickens and pigs, we could make this as: c + p = 20.

Since there are 2 legs per chicken and 4 legs per pigs and the total is 56, we could also put it as an equation: 2c + 4p = 55.

This fits the answer choice D, so the final answer is D.