Number theory — class composition check: Determine which total is impossible. In a class, the number of boys is 3 times the number of girls. Which of the following cannot be the total number of students? Choose the single impossible total.

Q: Number theory — class composition check: Determine which total is impossible. In a class, the number of boys is 3 times the number of girls. Which of the following cannot be the total number of students? Choose the single impossible total.

Given Boys = 3 × Girls ⇒ Total = Boys + Girls = 4 × Girls. Approach Total must be a multiple of 4. Check options 48 ✔ multiple of 444 ✔ multiple of 442 ✖ not a multiple of 440 ✔ multiple of 4 Final Answer 42

Difficulty: Easy

Correct Answer: 42

Explanation:

Given

Boys = 3 × Girls ⇒ Total = Boys + Girls = 4 × Girls.

Approach
Total must be a multiple of 4.

Check options
48 ✔ multiple of 444 ✔ multiple of 442 ✖ not a multiple of 440 ✔ multiple of 4

Final Answer
42

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