Q. If m : n = 3 : 2, then (4m + 5n) : (4m - 5n) is equal to:
Answer: 11 : 1
Notes: Given, $latex \frac{m}{n} = \frac{3}{2}&s=1$ $latex \therefore \frac{4m+5n}{4m-5n} = \frac{4\left ( \frac{m}{n} \right )+5}{4\left ( \frac{m}{n} \right )-5}&s=1$ $latex = \frac{4\times\frac{3}{2}+5}{4\times\frac{3}{2}-5}&s=1$ $latex = \frac{6+5}{6-5} = 11 : 1&s=1$ Hence option [B] is the right answer.

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