SOLUTION: A bag contains yellow and red blocks, there are 4 more red blocks than yellow. When pulling two blocks out, one at a time, you can not replace the first block. What is an expressio

Question 453680: A bag contains yellow and red blocks, there are 4 more red blocks than yellow. When pulling two blocks out, one at a time, you can not replace the first block. What is an expression that represents the probability of pulling out a red block first, then a yellow block?
Thank you.
Answer by ilana(307) (Show Source): You can put this solution on YOUR website!
Use x for the number of yellow blocks. Then there are x + 4 red blocks. So there are x + x + 4, or 2x + 4 blocks in all.
P(red) = (x + 4)/(2x + 4)
P(yellow after red) = x/(2x + 3)
So the probability is the product, x(x + 4)/(2x + 4)(2x + 3).
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