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The average age of four boys A B C and D…

September 7, 2022 by Prabhat

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The average age of four boys A, B, C and D is 5 years and the average age A, B, D, E is 6 years. C is 8 years old. The age of E is (in years) :

A. 12
B. 13
C. 14
D. 15

Answer: Option A

Here is complete explanation of The average age of four boys A B C and D….

Solution(By ExamCraze Team)

According to the question,
$$eqalign{ & frac{{A + B + C + D}}{4} = 5 cr & A + B + C + D = 20.....(i) cr & frac{{A + B + D + E}}{4} = 6 cr & A + B + D + E = 24.....(ii) cr} $$
If C = 8 years old, put the value of 'C' in equation (i)
∴ A + B + D + 8 = 20
A + B + D = 12.....(iii)
Put the value of equation (iii) in equation (ii)
12 + E = 24
E = 24 - 12
∴ E = 12