Simplification question for IBPS, SBI, RBI, clerk, PO, Railways, SSC

[Q] A man has some hens and cows. If the number of heads be 48 and the number of feet equals 140, then the number of hens will be:
(a) 62
(b) 26
(c) 36
(d) 63

Solution

Answer    (b)
Explanation
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Let the number of hens be x and the number of cows be y.
Then, x + y = 48 .... (i)
  and 2x + 4y = 140      x + 2y = 70 .... (ii)
Solving (i) and (ii) we get: x = 26, y = 22.
The required answer = 26.