You are drawing at random twice without replacement.
red marbles = 3
white marbles = 3
black marbles = 2
total marbles = 3+3+2 = 8
Probability of first getting a red marble = number of red marbles/ total marbles = 3/8
After removing one red marble,
total marble = 8-1 = 7
Now, probability of getting a black marble = 2/7
Probability of getting first a red and then a black marble = 3/8 × 2/7 = 3/28
Answer is 3/28