Multiple choice

The average weight of 40 Students is 32. If the Heaviest and Lightest are excluded the average weight reduces by 1. If only the Heaviest is excluded then the average is 31. Then what is the weight of the Lightest? 40 छात्रों का औसत वजन 32 है। यदि सबसे भारी और सबसे हल्के को बाहर रखा जाता है, तो औसत वजन में 1 से कमी आती है। यदि केवल सबसे भारी को बाहर रखा जाता है, तो औसत 31 है। फिर सबसे हल्का वजन क्या है?

  1. 30

  2. 31

  3. 32

  4. 33

  5. 34
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B Correct answer
Explanation

Total weight of 40 students = 40 × 32 = 1280. Excluding heaviest (H) and lightest (L), 38 students average 31, so their total = 38 × 31 = 1178. Therefore H + L = 1280 - 1178 = 102. When only H is excluded, 39 students average 31, so their total = 39 × 31 = 1209. Therefore H = 1280 - 1209 = 71. When both H and L excluded, 38 students total = 1178. So H + L = 1280 - 1178 = 102. Since H = 71, L = 102 - 71 = 31.

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