Mitiku D. answered • 04/01/15

Effective Tutoring

Katie,

Because the order with which it appears is not necessary we can try two different ways to answer the same question

probability that the first ball is blue = 6/13

probability that the second is not blue given that the first ball is blue = 7/12 - a blue's taken out

∴ probability that exactly one blue ball is chosen (6/13)(7/12)

probability that the first is not blue = 7/13

probability that the second ball is blue given that the first ball is not blue = 6/12 - one red ball's taken out

∴ probability that exactly one blue ball is chosen (6/12)(7/13)

I hope this helps Katie