Answer: 1/5
Upper left corner
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Step-by-step explanation:
There are 2 red out of 1+2+2 = 5 total. The fraction 2/5 represents the probability of picking red on the first selection.
Assuming the marble picked is not put back, we have 2 green out of 5-1 = 4 left over. So 2/4 = 1/2 is the probability of picking green as the second selection, based on the previous event in the first paragraph.
Multipling those fractions gets us (2/5)*(1/2) = (2*1)/(5*2) = 2/10 = 1/5 as the probability of picking red, then green with no replacement.