If 3a−5b/ 3a+5b =5, then a:b is equal to - IQ786

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If 3a−5b/ 3a+5b =5, then a:b is equal to

If 3a−5b/ 3a+5b =5, then a:b is equal to

5:1

4:6

4:9

5:2

Explanation

$\frac{3 a + 5 b}{3 a - 5 b} = 5 \Rightarrow 3 a + 5 b = 5 (3 a - 5 b)$
$\Rightarrow 3 a + 5 b = 15 a - 25 b \Rightarrow 12 a = 30 b$
$\Rightarrow \frac{a}{b} = \frac{3 0}{1 2} = \frac{5}{2} \Rightarrow a : b = 5 : 2$