In a group of cows and hens, the number of legs are 14 mo...
In a group of cows and hens, the number of legs are 14 more than twice the number of heads. The number of cows is
5
7
10
12
Correct answer is B
Let the number of cows be x and the number of hens be y.
Then, 4x + 2y = 2 (x + y) + 14 ⇔ 4x + 2y = 2x + 2y + 14 ⇔ 2x = 14 ⇔ x = 7.