A bag has 2 yellow, 7 red, and 1 green marble. What is the probability of picking a red marble, replacing it, and then picking a green marble?

A: 1/25
B: 1/50
C: 49/100
D: 7/100

Question

A bag has 2 yellow, 7 red, and 1 green marble. What is the probability of picking a red marble, replacing it, and then picking a green marble?

A: 1/25
B: 1/50
C: 49/100
D: 7/100

mertsj · Answer

How many marbles are in the bag?

anonymous · Answer

7+1+3=10 
 
10 marbles

mertsj · Answer

How many of them are red?

anonymous · Answer

7 red 1 green

mertsj · Answer

If there are 10 marbles in all and 7 of them are red, what is the probability of drawing out a red marble?

anonymous · Answer

7/10 .

but they're asking for green marble picking probability?

mertsj · Answer

Yes.  Good.  So you draw out the red marble, and then you put it back.  Now what is the probability of drawing out a green marble on your next draw?

anonymous · Answer

1/10 still because you're replacing the red marble.

mertsj · Answer

Multiply those two probabilities and you will have your answer.

anonymous · Answer

1/100?

anonymous · Answer

ops no

mertsj · Answer

Well, I'm not sure who taught you to multiply but if I multiply 7/10 by 1/10, I don't get 1/100

anonymous · Answer

multiply them by what?

anonymous · Answer

i didnt understand what you were multiplying

mertsj · Answer

What is the probability of drawing a red marble?