There are 50 boys in a class. One boy weighing 40 kg goes away and at the same time another boys joins the class . if the average weight of the class is thus decreased by 100 g find the weight of the new boy ?

32 kg

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40 kg

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35 kg

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37 kg

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Solution

The correct option is C 35 kg
Let the average weight of the class be x kg.
Total weight of 50 boys = 50x kg
If y is weight of the new boy, then
50x - 40 + y = 50 x (x - 0.1)
$\Rightarrow 50 x - 40 + y = 50 x - 5 \Rightarrow y = 35 k g$

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There are 50 boys in a class. One boy weighing 40 kg goes away and at the same time another boys joins the class . if the average weight of the class is thus decreased by 100 g find the weight of the new boy ?

The correct option is C 35 kgLet the average weight of the class be x kg.Total weight of 50 boys = 50x kgIf y is weight of the new boy, then50x - 40 + y = 50 x (x - 0.1)⇒50x−40+y=50x−5⇒y=35kg

The correct option is C 35 kg
Let the average weight of the class be x kg.
Total weight of 50 boys = 50x kg
If y is weight of the new boy, then
50x - 40 + y = 50 x (x - 0.1)
$\Rightarrow 50 x - 40 + y = 50 x - 5 \Rightarrow y = 35 k g$