There are 5 eligible Gujarati grooms of which 2 know Bengali and 5 eligible Bengali grooms of which 3 know Gujarati. There are 5 eligible Gujarati and 5 eligible Bengali brides. An eligible bride is agreeable to marry a boy of his community or a boy who knows her language. Grooms have no choice. In how many different ways 10 couples can be formed.
In 5 eligible Gujarati grooms, 2 know Bengali, remaining 3 should make their pair with Gujarati girls.
No. of methods to make such couple = 5.4.3 = 60
Similarly in 5 eligible Bengali grooms, 3 know Gujarati, remaining 2 should make their pair with Bengali girls.
No. of methods to make such couple = 5.4 = 20
No. of methods to make remaining 5 couple = 5.4.3.2.1 = 120
Hence total no. of methods = 60*20*120 = 144000
A mathematician is a blind man in a dark room looking for a black cat which isn't there
Charles R. Darwin
A MAN IS LIKE A FRACTION WHOSE NUMERATOR IS WHAT HE IS AND WHOSE DENOMINATOR IS WHAT HE THINK ABOUT HIMSELF LARGER THE DENOMINATOR SMALLER THE FRACTION