A farm has some horses and hens. The total number of heads of these animals is 55 and the total number of legs is 150. How many horses and how many hens are on the farm?
Given: Total heads = 55, Total legs = 150
Step 1: Let h = number of horses, c = number of hens
Step 2: From heads: h + c = 55 So c = 55 - h
Step 3: From legs: 4h + 2c = 150
Step 4: Substitute: 4h + 2(55 - h) = 150
Step 5: Simplify: 4h + 110 - 2h = 150 2h = 40 h = 20
Step 6: ∴ h = 20 horses, c = 35 hens
Answer: There are 20 horses and 35 hens on the farm.
Explanation
Using algebra: Let h = horses, c = hens. Each has one head, so h + c = 55. Horses have 4 legs, hens have 2 legs, so 4h + 2c = 150. Solving: from first equation, c = 55 - h. Substituting: 4h + 2(55 - h) = 150, giving 2h = 40, so h = 20 and c = 35.
Solution Steps
Step 1: Let h = number of horses, c = number of hens
Step 2: From heads: h + c = 55, so c = 55 - h
Step 3: From legs: 4h + 2c = 150
Step 4: Substitute: 4h + 2(55 - h) = 150
Step 5: Simplify: 4h + 110 - 2h = 150, so 2h = 40
Step 6: Therefore h = 20 horses, c = 35 hens