Boys And Girls Ka Mahasangram

The number of boys and girls in a class are in the ratio of 3 : 4 Find the strength of the class if there are 10 more girls than there are boys.

A committee of 4 boys and 3 girls is chosen from 8 boys and 5 girls. One of the boys is a brother of one of the girls. Probability that both are in the committee is

5 boys and 5 girls are sitting in a row randomly . The probability that boys and girls sits alternatively , is