Question

3 balls are drawn successively from a box containing 6red,4 white and 5 blue balls.Find the probability that they are drawn in order red,white and blue if:(a)each ball is replaced.(b)balls are not replaced

Answer 1

If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events.

6/15 * 4/15 * 5/15 = ?

Without replacement, there is one less ball total in the following draws.

6/15 * 4/14 * 5/13 = ?

Answer 2

one bag contains 4 white balls,2 black balls.another bag contains 3 white balls 5 black balls.if one ball is drawn from each bag. find that
a) both are white?
b) both are black?
c)one is white and one is black?

Answer 3

The sample point for 1st bag and 2nd bag are given by n(S1)=4+2=6, n(S2)=3+5=8, If one ball is drawn from each bag, the probability that both are white is given by: P(w1 n w2) ie, probability of 1st being white and 2nd being white. P(w1 n w2)=4/6*3/8=1/4
P(both are Black),P(B1 n B2)=2/6*5/8=5/24
P(one is W and one is B)=P(W1 n B2) or P(B1 n W2)=(4/6*5/8)+(2/6*3/8)=13/24. NB: "n" is used as interception which means multiplying and "or" is the union which means addition.