New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    Calculate the value of the expression: {2 X

    (P3 - Q3) - 30 X P X Q} if (P - Q) = 6 and (P2 + Q2) = 80
    A 464 Correct Answer Incorrect Answer
    B 564 Correct Answer Incorrect Answer
    C 462 Correct Answer Incorrect Answer
    D 542 Correct Answer Incorrect Answer

    Solution

    Given, (P - Q) = 6

    So, (P - Q)2 = 62

    Or, P2 + Q2 - 2PQ = 36

    Or, 2PQ = 80 - 36

    So, PQ = (44/2) = 22

    Now, Since, (P3 - Q3) = (P - Q)(P2 + Q2 + PQ)

    So, (P3 - Q3) = 6 X (80 + 22) = 6 X 102 = 612

    ATQ, So, {2 X (P3 - Q3) - 30 X P X Q} = (2 X 612) - 30 X 22
    = 1224 - 660 = 564

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