Question

Antonio has a total of 55 marbles. He has 15 green marbles and 12 red marbles. The rest of the marbles are blue. How many blue marbles does he have?

1) Check that the sum of b, 12, and 15 is 55.
2) Check that the difference of 55 and b is 12.
3) Check that the sum of b, 27, and 15 is 55.
4) Check that the difference of 55 and b is 15.

Answer 1

Antonio has a total of 55 marbles, out of which 15 are green and 12 are red. Subtracting the green and red marbles from the total, Antonio has 28 blue marbles.

Step-by-step explanation:

To solve the problem of how many blue marbles Antonio has, we need to do some simple arithmetic. Antonio has a total of 55 marbles. Out of these, 15 are green and 12 are red. To find the number of blue marbles, we subtract the number of green and red marbles from the total number of marbles.

Let's represent the number of blue marbles by b. First, we check the sum of the marbles:

1. Adding all the marbles together: b + 12 (red marbles) + 15 (green marbles) should equal 55. We can check if this is correct by plugging in b = 28 (since 55 - 12 - 15 = 28): 28 + 12 + 15 = 55. This is correct.
2. Checking the difference between the total marbles and red ones isn't necessary because we are looking for b.
3. Adding blue marbles to non-blue ones should also give us 55, so the sum of b + 27 (12 red + 15 green) = 55 is correct and is just another way of stating point 1.
4. Similarly, the difference between the total marbles and green ones isn't directly helping with finding the number of blue marbles.

Hence, Antonio has 28 blue marbles.