Answer:
0.064 = 6.4% probability that all three black socks are black if you replace each sock before selecting the next one
Explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
There are 10 socks, four of which are black.
The socks are replaced, which means for each time a sock is picked, there is a 4/10 = 0.4 probability of being black.
Three socks:
(0.4)^3 = 0.064
0.064 = 6.4% probability that all three black socks are black if you replace each sock before selecting the next one