If m : n = 3 : 2, then (4m + 5n) : (4m – 5n) is equal to:

If m : n = 3 : 2, then (4m + 5n) : (4m – 5n) is equal to:
[A]9 : 1
[B]11 : 1
[C]4 : 9
[D]9 : 4

11 : 1
Given,
\frac{m}{n} = \frac{3}{2}
\therefore \frac{4m+5n}{4m-5n} = \frac{4\left ( \frac{m}{n} \right )+5}{4\left ( \frac{m}{n} \right )-5}
= \frac{4\times\frac{3}{2}+5}{4\times\frac{3}{2}-5}
= \frac{6+5}{6-5} = 11 : 1
Hence option [B] is the right answer.

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