https://www.hackerrank.com/challenges/s10-mcq-6
In this challenge, we're reinforcing what we've learned today.
Task
A bag contains 3 red marbles and 4 blue marbles. Then, 2 marbles are drawn from the bag, at random, without replacement. If the first marble drawn is red, what is the probability that the second marble is blue?
Obs. this is just an question and answer problem in HackerRank.