SOLUTION: A box contains six red pens and three blue pens. (a) A pen is selected at random, the colour is noted and the pen is returned to the box. This procedure is performed a second, then

Algebra ->  Probability-and-statistics -> SOLUTION: A box contains six red pens and three blue pens. (a) A pen is selected at random, the colour is noted and the pen is returned to the box. This procedure is performed a second, then      Log On


   



Question 950285: A box contains six red pens and three blue pens. (a) A pen is selected at random, the colour is noted and the pen is returned to the box. This procedure is performed a second, then a third time. Find the probability of obtaining (i) three red pens, (ii) two red pens and one blue pen, in any order, (iii) more than one blue pen.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
P%28R%29=6%2F9=2%2F3
P%28B%29=3%2F9=1%2F3
.
.
I)P%283R%29=P%28R%29%2AP%28R%29%2AP%28R%29=%282%2F3%29%5E3=8%2F27
.
.
II) RRB, RBR, BRR
P=P%28RRB%29%2BP%28RBR%29%2BP%28BRR%29
P=3%2A%282%2F3%29%282%2F3%29%281%2F3%29
P=4%2F9
.
.
III) BBR,BRB,RBB,BBB
P=3%2A%281%2F3%29%281%2F3%29%282%2F3%29%2B%281%2F3%29%281%2F3%29%281%2F3%29
P=6%2F27%2B1%2F27
P=7%2F27