Multiple choice

If the average marks of class A is 86 and average marks of class B is 96 if the average marks of both the class is 10% more than average mark of class A then find the ratio of number of students of class A and B. यदि कक्षा A का औसत अंक 86 है, तथा कक्षा B का औसत अंक 96 है। यदि दोनों कक्षाओं का औसत अंक कक्षा A के औसत अंक से 10% अधिक है तो दोनों कक्षाओं के विद्यार्थियों की संख्या का अनुपात ज्ञात कीजिए ।

  1. 5 : 47

  2. 7 : 43

  3. 7 : 48

  4. 15 : 7

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Average of class A = 86, so combined average = 86 × 1.10 = 94.6. Let nA and nB be students in each class. Combined average = (86nA + 96nB)/(nA + nB) = 94.6. So 86nA + 96nB = 94.6nA + 94.6nB → 1.4nB = 8.6nA → nA/nB = 1.4/8.6 = 14/86 = 7/43. Ratio A:B = 7:43. The claimed answer B is correct.