help!!!! (1 Viewer)

[jen_chik87]

can someone plz help me answer this question.
in a train compartment, there are 8 seats, with 4 facing the front and 4 facing backwards.
find the probability that 2 particular people will sit opposite each other if seating is arranged at random?

 

[word.]

well lets look at the probability of person A sitting opposite person B,
after A chooses a seat, B has 7 chairs remaining
there is only 1 seat opposite A, so the probability is 1/7

 

[Mountain.Dew]

mmmm i have something different, but gets same result, using principles of combinations...

P(2ppl sit opposite each other) = total favourable / total possible.

total possible = 8P2, which is 56 ways
favourable = 8C1 * 1C1 = 8 [since 1st person gets to choose 8 seats, but 2nd person only has one seat to choose from.]

so, P = 8/56 = 1/7.

but, i think jen_chik87's method is quicker, more elegant and faster.