RBI Assistant Prelims practice question
Three quality-testing batches gave the following readings — Batch 1: 8 samples, average reading 90; Batch 2: 12 samples, average reading 70; Batch 3: 20 samples, average reading 60. Find the combined average reading of all three batches together.
From a RBI Assistant Prelims Quantitative Aptitude practice set · Quantitative Aptitude
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Correct answer: (D) 69 units
Total samples = 8 + 12 + 20 = 40. Group-wise sums: 8 × 90 = 720, 12 × 70 = 840, 20 × 60 = 1200. Combined sum = 720 + 840 + 1200 = 2760. Combined average = 2760 ÷ 40 = 69 units.
हिंदी में प्रश्न
तीन गुणवत्ता-परीक्षण बैचों की रीडिंग इस प्रकार है — बैच 1: 8 नमूने, औसत रीडिंग 90; बैच 2: 12 नमूने, औसत रीडिंग 70; बैच 3: 20 नमूने, औसत रीडिंग 60। तीनों बैचों को मिलाकर संयुक्त औसत रीडिंग ज्ञात कीजिए।
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सही उत्तर: (D) 69 यूनिट
कुल नमूनों = 8 + 12 + 20 = 40. समूह-वार योग: 8 × 90 = 720, 12 × 70 = 840, 20 × 60 = 1200. संयुक्त योग = 720 + 840 + 1200 = 2760. संयुक्त औसत = 2760 ÷ 40 = 69 यूनिट.
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