Question 3172: there are 41 pigs and chikens on a farm. There are 100 legs counted altogether, how many of each animal are there? Found 2 solutions by gsmani_iyer, WannabeCAgirl83:Answer by gsmani_iyer(201) (Show Source):
Step 1
Finding Equations:
There are 41 pigs and chickens on a farm.
p + c = 41 → Eqn 1
There are 100 legs counted altogether.
4p + 2c = 100 → Eqn 2
(Note that a pig has 4 legs while a chicken has 2. Therefore it’s 4p and 2c.)
Step 2
Isolating p in Eqn 1:
p + c = 41 | - c on both sides
p = 41 - c
Step 3
Substituting p in Eqn 2 with the term found for p in step 2. Then isolating c:
4(41 - c) + 2c = 100
164 - 4c + 2c = 100 | re-arranging
164 - 2c = 100 | - 164 on both sides
- 2c = - 64 | : - 2
c = 32 → There are 32 chicken.
Step 4
Substituting c in Eqn 1 by the value found for c in step 3. Then again isolating p:
p + c = 41
p + 32 = 41 | - 32 on both sides
p = 9 → There are 9 pigs.