Answer:
51
Step-by-step explanation:
Given parameters:
Number of heads = 30 heads
Number of legs = 84 legs
Unknown:
Number of chickens and pigs = ?
Solution:
Since a chicken has one head, the number of chicken is the same as the number of heads;
Number of chicken = 30
A pig has 4 legs,
Number of pigs = = 21pigs
Total number of pigs and chickens = 30chickens + 21 pigs = 51