Multiple choice

The question given below is followed by some statements. Read the question carefully and statements and determine which of the given statements is/are necessary/required to answer the question. नीचे दिए गए प्रश्न के बाद कुछ कथन दिए गए हैं। प्रश्न को ध्यान से पढ़ें और निर्धारित करें कि दिए गए कथनों में से कौन सा / से प्रश्न का उत्तर देने के लिए आवश्यक / आवश्यक है /हैं । What is the average weight of boys in the class? कक्षा में लड़कों का औसत वजन कितना है? I. Average weight of all the 60 students is 45 kg. II. Average weight of girls is 50 kg. III. Total weight of all the boys together is 1250 kg. I. सभी 60 छात्रों का औसत वजन 45 किलोग्राम है। II. लड़कियों का औसत वजन 50 किलोग्राम है। III. एक साथ सभी लड़कों का कुल वजन 1250 किलोग्राम है।

  1. Only II and III

  2. I and either II or III

  3. Any two of these

  4. All I, II and III

  5. Cannot be determined
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let number of boys = b, girls = g. Total students = 60. From I: Total weight = 60×45 = 2700 kg. From II: Girls' average = 50 kg, so total girls' weight = 50g. From III: Total boys' weight = 1250 kg. Average boys' weight = 1250/b. We need b to find this average. Using I and II: 2700 = 1250 + 50g, so 50g = 1450, g = 29. Then b = 60-29 = 31. Boys' average = 1250/31 ≈ 40.32 kg. All three statements are necessary - I gives total, II gives girls' average to find g, III gives boys' total weight.

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