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? A student represents the number of blue marbles as the variable b and solves this problem by writing an equation. Which strategy could help check the student’s answer?

Options:

A) Check that the sum of b, 12, and 15 is 55.
B) Check that the difference of 55 and b is 12.
C) Check that the sum of the b, 27, and 15 is 55.
D) Check that the difference of 55 and b is 15.

Answer 1

The sum of the blue marbles, represented by b, should be: 55 - 15 - 12 = 28. So the student's answer is correct if the sum of b, 12, and 15 is indeed 55.

Step-by-step explanation:

To check the student's answer, we can use option A) Check that the sum of b, 12, and 15 is 55.

We know that Antonio has a total of 55 marbles. We also know that he has 15 green marbles and 12 red marbles. Therefore, the sum of the blue marbles, represented by b, should be:

55 - 15 - 12 = 28.

So the student's answer is correct if the sum of b, 12, and 15 is indeed 55.