In a bag are 3 red balls and 7 green balls, indistinguishable by touch. Two extractions are made, with the first ball being returned to the bag before the second extraction. What is the probability of extracting 2 green balls?
A) 9/100
B) 42/90
C) 51/100
D) 7/10
E) 49/100
IMAT 2024 · Question 50
Q50 - Probability
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The correct answer is E) 49/100.
The first ball goes back in, so both draws are the same: 7/10 each time.
7/10 × 7/10 = 49/100
42/90 is the answer without putting the ball back.
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