Solved UPSC CDS/OTA Question
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Q · Average Medium · 45s
The average weight of A, B and C is 84 kg. If D joins the average weight becomes 80 kg. If another person E, who is 3 kg heavier than D replaces A, then the average weight of B, C, D and E becomes 79 kg. Find the weight of A?
TopicAverage
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained - no skipped algebra.
A + B + C = 84 X 3 ....... (1)
A + B + C + D = 80 x 4 .......(2)
B + C + D + E = 79 X 4 .......(3)
By subtracting (2) - (3)
A – E = 4
A = 4 + E
(84 X 3) + D = 80 X 4
D = 68
E = D + 3 (Given)
then, E = 71
and A = 71 + 4 = 75
Final Answer: Option D - 65 kg