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Three numbers are in the ration 1:2:3. If the sum of their cubes is 98784, then the numbers are

A) 7,14,28
B) 14,28,42
C) 6,12,18
D) 12,18,36

Correct Answer:


B) 14,28,42

Description for Correct answer:

Let the numbers be x,2x,3x.
Then \( \Large \left(x \right)^3 +\left(2x \right)^3+\left(3x \right)^3\) = 98784.

\( \Large x^3+8x^3+27x^3 \) = 98784

\( \Large 36x^3 \) = 98784

\( \Large x^3 \) = \( \Large \frac{98784}{36} \)

\( \Large x^3 \) = 2744

X = \( \Large \sqrt[3]{2744} \) = 14

Hence the numbers are 14,28,42

Part of solved Number System questions and answers : >> Aptitude >> Number System

Comments

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