Answer: 
Step-by-step explanation:
Formula for probability :-

Given : One bag contains 3 white marbles and 5 black marbles, and a second bag contains 4 white marbles and 6 black marbles.
Probability of drawing a black marble from first bag 
Probability of drawing a black marble from second bag 
Since the event of drawing marbles from each bag is independent, then
If a person draws one marble from each bag, then the probability that both marbles are black will be the product of both events :-

Hence, the required answer = 