john had a bag of 10 marbles (2 Green, 4 Blue, 1 Yellow, 2 Red) What is the probability that john selects a green marble, replaced it, and then selects a green marble?

Hector and alex traded video games. alex gave hector one fourth of his video games in exchange for 6 video games. then he sold 3 video games and gave 2 video games to his brother. alex ended up with 16 video games. how many video games did alex have when he started?