Question

3. There were 100 cows and chickens on a farm. There were 220 lesser chicken legs than cow legs. How many cows are there? "Assume all "→ Add 220 or subtract 220? Gap in difference between 1 cow and 1 chicken → Total gaps + 1 gap ​

Answer 1

there are 70 cows

Explanation:

Let x = no. of cows

y = no. of chickens

there were 100 cows & chicken ⇒ x + y = 100 ... [1]

there were 220 lesser chicken legs than cow legs ⇒ 4x - 2y = 220 ... [2]

[1] & [2]

x + y = 100 ⇔ x + y = 100

4x - 2y = 220 ⇔ 2x - y = 110

-------------------- (+)

3x = 210

x = 70