probability

1.
P(2 cards are drawn with a sum of 5)
= (Draw a 2 and then 3) + (Draw a 3 and then 2)
= (2/5) x (1/4) + (1/5) x (2/4)
= (1/10) + (1/10)
= 2/10
= 1/5


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2.
P(hitting the target) = 2/3
P(missing the target) = 1 - (2/3) = 1/3

P(missing the target twice when shooting twice)
= (1/3)²
= 1/9

P(hitting the target at least once when shooting twice)
= 1 - (1/9)
= 8/9