Three unequal resistors in parallel are equivalent to a resistance $1\, ohm$. If two of them are in the ratio $1 : 2$ and if no resistance value is fractional, the largest of the three resistances in $ohms$ is
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Two resistance are in ratio $1 : 2$ and third resistance is $R$
So, $\frac{1}{x} + \frac{1}{{2x}} + \frac{1}{R} = 1 \Rightarrow x = \frac{3}{2}\left( {\frac{R}{{R - 1}}} \right)$
As, resistance is not fractional $ \Rightarrow $ $\frac{R}{{R - 1}} = 2$
$ \Rightarrow $ $x = 3,\,R = 2,\,2x = 6$
Hence, the value of largest resistance $= 6\,\Omega$.
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