Of three numbers, first is twice second and second is thrice third. If average of three numbers is 1

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4.Average

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Of the three numbers, the first is twice the second and the second is thrice the third. If the average of the three numbers is $10,$ the numbers are

A

$18,3,9$

B

$9,3,18$

C

$3,9,18$

D

$18,9,3$

Solution

Let, the numbers be $2 x, x$ and $\frac{1}{3}$

Then, average $=\frac{2 x+x+\frac{x}{3}}{3}=10 \Rightarrow \frac{9 x+x}{3 \times 3}=10$

or, $\frac{10 x}{9}=10,$ or, $x=9$

Hence, the numbers are $18,\,9$ and $3 .$

Standard 13

Quantitative Aptitude

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