Question 171639
This is a case of "sampling without replacement"
In this problem, you first find the probability that a white marble is drawn, expressed as {{{P(W)}}}. You have correctly found this to be {{{P(W) = 3/8}}}.
Now, you need to find the probabilty that a blue marble was next drawn, given that a white marble was previously drawn. This is expressed as P(B|W) and, because there are now only 7 marbles (from an initial 8 marbles) in the bag, this would be expressed as: P(B|W) = 1/7.
Now you can find the probability that the first marble drawn (without replacement) was white and the second mable was blue:
P(W and B) = P(W)*P(B|W) = {{{(3/8)*(1/7)= 3/56}}} = {{{0.0536}}}