Question

What's the probability? Please read carefully

Answer 1

Answer: 5/14

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Explanation:

A = event of drawing a blue card on the first selection
B = event of drawing a blue card on the second selection

P(A) = probability of drawing a blue card on the first selection
P(A) = (number of blue cards)/(number of cards total)
P(A) = 5/8

P(B|A) = probability of getting a second blue card GIVEN the first card is blue
P(B|A) = (number of blue cards left after event A happens)/(number of cards left)
P(B|A) = 4/7

The fact that B depends on A is very important. This happens because the first card is not replaced

Multiply the fractions
P(A)*P(B|A) = (5/8)*(4/7)
P(A)*P(B|A) = (5*4)/(8*7)
P(A)*P(B|A) = 20/56
P(A)*P(B|A) = 5/14

Which is why the answer is the fraction 5/14