In a group of 3 girls and 4 boys, there are two boys $B_1$ and $B_2$. The number of ways, in which these…
In a group of 3 girls and 4 boys, there are two boys $B_1$ and $B_2$. The number of ways, in which these girls and boys can stand in a queue such that all the girls stand together, all the boys stand together, but $B_1$ and $B_2$ are not adjacent to each other, is :
96
144
120
72
Solution
Total - when $\mathrm{B}_1$ and $\mathrm{B}_2$ are together $=2!(3!4!)-2!(3!(3!2!))=144$
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