A = event that you select a black sweater
P(A) = 2/5 since there are 2 black out of 2+3 = 5 total
After you make a selection, we have the event
B = event that you select another black sweater assuming event A has happened already
P(B) = 1/4 because there's 1 black sweater left out of 5-1 = 4 left over
Multiply the probabilities
P(A and B) = P(A)*P(B)
P(A and B) = (2/5)*(1/4)
P(A and B) = 2/20
P(A and B) = 1/10
The answer as a fraction is 1/10
In decimal form, it is 0.1
As a percent, the answer is 10%