13 spades, 52 cards total
probability of drawing a single spade = 13/52 = 1/4
If we replace that card, then the probability of drawing of drawing a spade is still 1/4 as nothing has changed
Overall, the probability of getting two spades in a row is (1/4)*(1/4) = 1/16
note: the two events are independent because of the replacement happening
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The answer as a fraction is 1/16
As a decimal, that would be 0.0625 which converts to 6.25%