Five different books (P, Q, R, S, T) are to be arranged on a shelf. The books R and S are to be arranged first and second, respectively from the right side of the shelf

Q. Five different books (P, Q, R, S, T) are to be arranged on a shelf. The books R and S are to be arranged first and second, respectively from the right side of the shelf. The number of different orders in which P, Q and T may be arranged is .

(A) 2

(B) 6

(C) 12

(D) 120

Ans: 6

Solution:

Here R and S are fixed in 1st and 2nd place from right.

Therefore arrangement of
P,Q,T= ³P_³=3!=6