Question

Suppose that six students, including Madhu and Puja, are having six beds arranged in a row. Further, suppose that Mudhu does not want a bed adjacent to Puja. Then the number of ways, the beds can be allotted to students is
A. 384
B. 264
C. 480
D. 600

Answer 1

Six students, including Madhu and Puja, can be adjusted on six beds in 6! ways. Puja and Madhu can be adjusted on two adjacent beds in 2! ways. Considering these adjacent beds as one and the remaining 4 beds can be arranged beds in `5!xx2!` ways.
Hence, Number of ways in which Puja and Madhu are not on adjacent beds `=6!-5!xx2!""=480`.