Question
The average of three numbers is 21. The first number is
double the second, and the third number is double the first. Calculate the sum of the first and third numbers.Solution
Let 2ndĀ number be 'x' Therefore, 1stĀ number = 2x And, 3rdĀ number = 2 X 2x = 4x Therefore, x + 2x + 4x = (21 X 3) = 63 ATQ; 7x = 63 Or, x = 9 Required sum = 2x + 4x = 6x = 6 X 9 = 54 Hence, option a.
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