Please let me know the answer!!!

Question

A sack contains 4 blue chips, 3 white chips, and 3 yellow chips. A chip is chosen and then put back in the sack, and then another chip is chosen. What is the probability that both chips chosen are blue?

Answer 1

The probability of picking the first blue chip is:

 

     P(blue) = (Number of blue chips)/(Total number of chips) = 4/(4+3+3) = 4/10 = 2/5

 

Since you put the chip back, the number of blue chips and the total number of chips are the same, so the probability of picking a blue chip on the second draw is also 2/5.  So the probability of picking two blue chips on successive draws is:

 

     P(2 blue) = P(blue)·P(blue) = 2/5 · 2/5 = 4/25