Read the word problem. 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?
Answer
A
Check that the difference of 55 and b is 15 .
B
Check that the sum of the b , 27 , and 15 is 55 .
C
Check that the difference of 55 and b is 12 .
D
Check that the sum of b , 12 , and 15 is 55 .
Explanation
The blue marbles are the amount left after counting the 15 green and 12 red marbles. To check the answer, add all three groups and make sure the total is 55: b + 12 + 15 = 55. This is the strategy in choice D.
AI-written and checked against the verified answer.