Problem Solving

If X = [(1728)^2 (392) + (392)^2 (532) + (532)^2 (1728)] & Y = 3.1728.392.532, then

A. X > Y
B. X < Y
C. X > Y
D. X < Y
E. X = Y
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Hit & Trial Approach...


This question wants to test your knowledge about relationship betn. (a^2 b + b^2 c + c^2 a) & 3abc.

Whether (a^2 b + b^2 c + c^2 a) < > = 3abc ?

Simple take random values of a, b, & c as say 1, 2, & 3.

This gives (a^2 b + b^2 c + c^2 a) = 23;

Whereas 3abc = 3.1.2.3 = 18.

So (a^2 b + b^2 c + c^2 a) > 3abc for this set of values. You may try for other sets of smaller values. If X > Y is true always,

then [(1728)^2 (392) + (392)^2 (532) + (532)^2 (1728)] > 3.1728.392.532

Take Away...

For any set of +ive values of a, b, & c => (a^2 b + b^2 c + c^2 a) > 3abc