A boy have 5 coloured pegs; blue, red, yellow,green and purple. He arranged it randomly in a single horizontal row of 5 pegs. Find the probability the pegs are arranged such that

a) blue and yellow occupies both ends
b) green is immediately on the left of purple
c) blue,red and yellow are together

Question

A boy have 5 coloured pegs; blue, red, yellow,green and purple. He arranged it randomly in a single horizontal row of 5 pegs. Find the probability the pegs are arranged such that

a) blue and yellow occupies both ends
b) green is immediately on the left of purple
c) blue,red and yellow are together

anonymous · Answer

(a)
P(blue and yellow occupies both ends) = 1/5 x 3/5 x 2/5 x 1/5 x 1/5 = 6/3125
(b)
p(green is immediately on the left of purple) = [(1/5x1/5 )x 3/5 x2/5 x1/5 ]x4 =24/3125
(c)
 P(blue,red and yellow are together) = (3/5 x2/5 x 1/5) x 2/5 x 1/5 x3 = 36/3125
Not sure. Sorry