SSC CGL 2023 PYQ — Question 63

SSC CGL - 14 July 2023 - Shift 2 • Quantitative Aptitude • Q63

What is the value of a3 + b3 + c3 if (a + b + c) = 0?

Show answer & explanation

Correct answer: C

Explanation

The correct answer is Option 3 i.e. 3abc.

Given that

the value of a3 + b3 + c3 

if (a + b + c) = 0

⇒ a + b = - c

Cube on both sides 

⇒  a3 + 3a2b + 3ab2 + b3 = -c3

⇒ a3 + b3 + c3 + 3ab(a + b) = 0

Put value of a + b = -c

⇒ a3 + b3 + c3 - 3abc = 0

⇒ a3 + b3 + c3 = 3abc