RPF Sub-Inspector (Executive) 2019 · Question 66 of 82

a . ix The average weight of 103 notebooks in a box is 10.3 kg. When a new notebook is added to the box, the average weight goes up to 10.4 kg. Tell the weight of the new notebook.

A20.7 kgCorrect
B20.3 kg
C20.5 kg
D20.9 kg

Answer: A. 20.7 kg

Explanation

Let be the sum of the weight of notebooks and N is the weight of new notebook. By using the above formula, S/103 = 10.3 = 103 10.3 =1060.9 ----(1) . When the new notebook is added, + N)/104 = 10.4 S+N=1081.6 a ix N = 1081.6-1060.9 (from equation (1)) N = 20.7 .

Source: RPF SI Previous Year Paper 06-Jan-2019 — answer key & detailed solutions (ixambee PDF) · reliable-secondary

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