There are an equal number of boys and girls in a class. If 12 girls leave the…
2026
There are an equal number of boys and girls in a class. If 12 girls leave the class, the number of boys becomes twice the number of girls remaining. What was the total number of students in the class originally?
Answer: B. 48 — Concept: For a word problem with two equal, changing quantities, represent both with one variable, translate the stated relationship into a linear equation,…
- A.
36
- B.
48
- C.
78
- D.
62
Attempted by 57 students.
Show answer & explanation
Correct answer: B
Concept: For a word problem with two equal, changing quantities, represent both with one variable, translate the stated relationship into a linear equation, and solve for the variable.
Application: Let the number of boys = the number of girls = x, since the class starts with equal boys and girls.
After 12 girls leave, the number of girls remaining = x - 12. The condition states that the number of boys becomes twice the girls remaining, so:
x = 2(x - 12)
x = 2x - 24
24 = 2x - x
x = 24
Total number of students originally = boys + girls = x + x = 2x = 2 × 24 = 48.
Cross-check: With x = 24, boys = 24 and girls = 24. After 12 girls leave, girls remaining = 24 - 12 = 12, and boys (24) is indeed twice 12. This confirms the total of 48 students.