Hi maxpowers,
No of people to be seated are J,R,C,B,H and P
Now J always wants to sit next to R Let si join them together and call them X
Now we have to arrange X,C,B,H,P ( I hope you agree )
There are 5 people here and can earranged in 5! ways. But that is not it.
We made X out of J and R right. J and R can be arranged as JR or RJ so we have two combinations here. Had we said only JR is allowed then there would have been 5! combinations.
Since we say RJ is also valid we have 2 * 5! ways.
But these combinations also include those in which C and B are together
So what are the ways in which J&R are together and C&B are together?
Let us call J&R as X and C&B as Y
So we have X,Y,H,P to be seated in 4! ways
But X has 2 hidden combinations as I explained above
Y also has 2 hidden combinations
In total there are 2*2*4! combinations in which J&R are together and C&B are together.
If you subtract this number from the number in whihc only J&R are together you will be left with combinations in which only J&R are together
So answer is 2*5! - 2 * 2 * 4! = 144
I hope I have explained it properly.