Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-11

In a farm, there are cows and hens. If heads are counted there are 180, if legs are counted there are 420. The number of cows in the farm is                                                                                          [WBSSC 2015]

A) 150

B) 30

C) 130

D) 50

Correct Answer: B

Solution :

Let the number of cows and hens in the farm be x and y, respectively.

Then, \[x+y=180\] (i)

and \[4x+2y=420\]

\[\Rightarrow \] \[2x+y=210\] (ii)

On subtracting Eq. (i) from Eq. (ii), we get

\[x=30\]

Hence, there are 30 cows in the farm.