Question

If (5√P - 7√Q) = 5, [1.5P = 4Q-(R/3)+9] and (√P/√Q) = 1.6, then find out the value of ‘R’.

A 45 Correct Answer Incorrect Answer
B 27 Correct Answer Incorrect Answer
C 39 Correct Answer Incorrect Answer
D 42 Correct Answer Incorrect Answer
E None of the above Correct Answer Incorrect Answer

Solution

(5√P - 7√Q) = 5    Eq.(i) (√P/√Q) = 1.6 √P = 1.6√Q    Eq.(ii) Put Eq.(ii) in Eq.(i). (5x1.6√Q - 7√Q) = 5 (8√Q - 7√Q) = 5 √Q = 5    Eq.(iii) So Q = 25     Eq.(iv) Put Eq.(iii) in Eq.(ii). √P = 1.6x5 √P = 8 So P = 64 [1.5P = 4Q-(R/3)+9] Put the value of ‘P’ and ‘Q’ in the above equation. [1.5x64 = 4x25-(R/3)+9] [96 = 100-(R/3)+9] [96 = 109-(R/3)] (R/3) = 109-96 (R/3) = 13 Value of ‘R’ = 13x3 = 39

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