I have a bag with red and green marbles in it. At the moment, the ratio of red marbles to green marbles is 3:2. If I add 5 red marbles and 5 green marbles, the ratio will be 4:3. How many red marbles will be in the bag after I add more?
because both sides of the ratio increased by 1 after we added 5 to both sides, that means the ratio is simplified by 5. so, to find out how many are in the bag after you add more, you simply multiply by 5. This means you have 20 red marbles after you added more marbles.