Alex has a bag of marbles. Each marble is red or blue, and the ratio of red to blue marbles is 3 : 5. After Alex adds 10 red marbles to the bag, the ratio of red to blue marbles is 2 : 3. How many blue marbles are in Alex’s bag?
Alex has a bag of marbles. Each marble is red or blue, and the ratio of red to blue marbles is 3 : 5. After Alex adds 10 red marbles to the bag, the ratio of red to blue marbles is 2 : 3. How many blue marbles are in Alex’s bag?
How many blue marbles are in Alex’s bag?