Answer:
1/20
Step-by-step explanation:
Remark: Not huge
Total number of Socks: 6 + 6 + 4 = 16
P(First Black Sock): 4/16 = 1/4
The second Sock needs to be discussed a bit. The number of black socks has gone down to 1 and the total will always go down by 1.
Second Sock: 3 Black / 15 Total = 3/15 = 1/5
Combined Probability: 1/4 * 1/5 = 1/20