Question 1071538: A box contains 60 colored balls: 45 of the balls are purple,and 30 of the purple balls have stars on them. if a purple ball being randomly chosen and a ball with stars being randomly chosen are independent events,how many of the 60 colored balls have stars on them?
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! you have 60 colored balls.
45 of them are purple.
30 of the purple balls have stars on them.
break out the purple balls with start on them into a separate category and you have:
P = 15 purple balls.
S = 30 purple balls with stars on them.
N = 15 balls that are not purple and have no stars on them.
the total number of balls is equal to 60.
the probability that you will get a purple ball with a star on it is 30/60.
the probability that you will get a purple ball without a star on it is 15/60.
the probability that you will get a balls that is not purple and doesn't have a star on it is 15/60.
since you have already stated that 30 of the purple balls have stars on them, then your question is very confusing, since you are asking how many of the purple balls have starts on them.
the answer is 30.
please look at what you are asking again and reformulate your problem so that we can understand exactly what it is that you are looking to find.
do the balls that are not purple have stars on them?
are you drawing from the pot of balls one time, two times, three times.
how many times are you drawing a ball at random from the pot of balls?
a typical problem might ask:
what is the probability of getting a purple ball with a start on it if 2 balls are drawn from the pot randomly.
there is also the question of with replacement or without replacement.
if you draw a ball out of the pot and then put it back when you draw again, that's a different probability than when you draw a ball from the pot and then draw again without replacing it.
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