In a school ratio of no. of teachers, boys and girls was 1 : 7 : 5. When 8 new teachers join and 9 girls left the school the ratio of teacher to student becomes 1 : 7. Find the number of remaining girls in school.
Answer & explanation
Correct answer: option 3
Teacher : Boys : Girls
1 : 7 : 5
⇓ ⇓
OR Teacher : ↔ Students ↔
ATQ 1 : 12 (7+5)
+8 : -9
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1 : 7
Now,
\(\frac{1R + 8}{12R - 9}\) = \(\frac{1}{7}\)
⇒ 7 R + 56 = 12 R - 9
5 R = 65 [ No. of girls initially (5)]
-9
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56 [ No. of girls now]
