When a girl weighing 90 kgs left a class, the average weight of the remaining 119 students increased by 400 g. What is the average weight of the remaining 119 students? A) 124 B) 138 C) 145 D) 116

1 Answer

Answer :

 B

Let the average weight of the 119 students be X.

Therefore, the total weight of the 119 of them will be 119X.

The questions states that when the weight of this student who left is added, the total weight of the class

= 119X+90

When this student is also included, the average weight decreases by 0.4 kgs.

(119X+90)/120=X−0.4

⇒119X+90=120X−48

 ⇒X=138

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