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IBPS Clerk Prelims Model Paper 3

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Question : 1 of 100

Marks: +1, -0

\frac{117 \times 117 \times 117 - 98 \times 98 \times 98}{117 \times 117 + 117 \times 98 + 98 \times 98}

215
311
19
29
None of these

Solution:

Concept:

Use the identity

a^3-b^3=(a-b)(a^2+ab+b^2)

.

Explanation:

Let

a=117

and

b=98

.

The numerator is

a^3-b^3

.

The denominator is

a^2+ab+b^2

.

So the expression becomes

\frac{a^3-b^3}{a^2+ab+b^2}

.

Substitute the identity:

\frac{(a-b)(a^2+ab+b^2)}{a^2+ab+b^2}

.

Cancel the common factor

a^2+ab+b^2

.

Result

=a-b=117-98=19

.

Answer:

19

(Option C).

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