Question

There are six teachers. Out of them, two teach physics, other two teach Chemistry and the rest two teach Mathematics. They have to stand in a row such that Physics, Chemistry and Mathematics teachers are always in a set. The number of ways in which they can do, is :

A.
24
B.
48
C.
36
D.
12

Accepted Answer

B. There are 3 sets of subject teachers (Physics, Chemistry, Math). The 3 sets can be arranged among themselves in $3! = 6$ ways. Within each set, the 2 teachers can be arranged in $2! = 2$ ways. Total ways = $3! 	imes 2! 	imes 2! 	imes 2! = 6 	imes 8 = 48$.

Permutations with subject groups

Explanation

Practise this under exam conditions