Question

    If p = 35 - q - r and pq + r(p + q) = 324, then find the

    value of (p² + q² + r²).
    A 592 Correct Answer Incorrect Answer
    B 560 Correct Answer Incorrect Answer
    C 577 Correct Answer Incorrect Answer
    D 609 Correct Answer Incorrect Answer

    Solution

    We have, p = 35 - q - r
    So, p + q + r = 35
    And, pq + r(p + q) = 324
    Or, pq + qr + pr = 324
    Using, (p + q + r)² = p² + q² + r² + 2(pq + qr + pr)
    35² = (p² + q² + r²) + 2 × 324
    1225 = (p² + q² + r²) + 648
    p² + q² + r² = 577

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