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SSC CGL 2022 PYQ — Question 58

SSC CGL - 02 Dec 2022 - Shift 3 • Quantitative Aptitude • Q58

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If a + b + c = 6, a2 + b2 + c2 = 14 and ab + bc + ca = 11, then what is the value of a3 +  b3  + c3 - 3abc?

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Correct answer: C

Explanation

The correct answer is Option 3 i.e. 18.

Given:

a + b + c = 6, a2 + b2 + c2 = 14 and ab + bc + ca = 11

Formula used:

a3 +  b3  + c3 - 3abc = (a + b + c)(a2 + b2 + c2 - (ab + bc + ca))        ---- (1)

Calculations:

Using equation (1), we get

a3 +  b3  + c3 - 3abc = (6)(14 - 11)

⇒ 6 × 3 = 18