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RRB ALP CBT I 26 Nov 2024 Shift 1 Paper

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Question : 18 of 75

Marks: +1, -0

Evaluate 297*303

89991
89091
90991
79991

Solution:

Concept:

Use the algebraic identity

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

to simplify the multiplication.

Explanation:

Write

297

as

(300 - 3)

and

303

as

(300 + 3)

.

So,

297 \times 303 = (300 - 3)(300 + 3)

.

Applying the identity:

(300 - 3)(300 + 3) = 300^2 - 3^2

.

Now,

300^2 = 90000

and

3^2 = 9

.

Therefore,

90000 - 9 = 89991

.

Answer:

297 \times 303 = 89991

Correct option: A. 89991

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