Let’s take AB as pair 1, CD as P2 and EF as P3

The number of ways these 3 pairs can be arranged = 3! = 6

But each pair can be seated in 2 ways = AB or BA

The number of ways, the 6 friends can be arranged (desired way) = 6 x 2^3 = 48

Total number of ways the 6 friends can be arranged = 6!

Probability = 48/6! = 1/15

Thank you so much