Question

12 is divided into two parts such that the sum of their reciprocals is `12/35` . Find the two parts.

A 5 and 7 Correct Answer Incorrect Answer
B 6 and 6 Correct Answer Incorrect Answer
C 4 and 8 Correct Answer Incorrect Answer
D 9 and 3 Correct Answer Incorrect Answer
E None of these Correct Answer Incorrect Answer

Solution

Let the 1st part = x ,    ∴ 2nd part = 12 - x = `1/x+1/(12-x)=12/35=>((12-x)+x)/(x(12-x))=12/35=>(12-x+x)/(12x-x^2)=12/35`             420  = 144 x  -12 x²             ⇒ 12 x²-144x +420  x²- 12x +35 = x ²- 7x  - 5x  + 35  x(x -7) - 5(x -7)  x = 7 or 5 ∴ Two parts are 7 and 5

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