SSC CPO SI and ASI 2011 Paper

(4) Let the number of cows or herdsmen be n.
Total number of legs of both cows and herdsmen = 4n + 2n = 6n.
and, Number of heads is 2n.
According to question,
4 × 2n – 28 = 6n,
⇒ 2n = 28,
⇒ n = 14