For which segment lengths is _QS parallel to _MN?

Probability P(getting exactly 1 colour repeated twice) = 1/128

Step-by-step explanation:

Green ball=1, red ball = 1 , Blue ball=1 , yellow ball =1

Assuming the two colours are green balls

P(Green ball)= 1/4

P( green ball)= 1/4

P( blue ball)= 1/4

P(yellow or white)= 2/4

P(getting exactly 1 colour repeated twice)= 1/4 ×1/4 ×1/4 ×2/4 = 2/256 =1/128