a bag contians 15 marbles: 7 blue marbles and 8 red marbles. Reese chooses two marbles one at a time without replacing the first marble which is the probability that Reese chooses 2 blue marbles

Megan and desmond each add the same amount of water to their aquarium megan makes 5 ml of chemical solution with every gallon of water for her aquarium desmond mixed 8 ml of chemical solution for every 2 gallon of the water for his aquarium.