Question

If the value of 1/2+1/6+1/? Is 4 then what is the value of '?' ?

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{the}\mathrm{required}\mathrm{number}=\mathrm{x} \\ \mathrm{Now},\frac{1}{2}+\frac{1}{6}+\frac{1}{\mathrm{x}}=4 \\ \Rightarrow \frac{3\mathrm{x}+\mathrm{x}+6}{6\mathrm{x}}=4 \\ \Rightarrow \frac{4\mathrm{x}+6}{6\mathrm{x}}=4 \\ \Rightarrow 24\mathrm{x}=4\mathrm{x}+6 \\ \Rightarrow 24\mathrm{x}-\mathrm{x}=6 \\ \Rightarrow 20\mathrm{x}=6 \\ \Rightarrow \mathrm{x}=\frac{6}{20}=\frac{3}{10} \end{gathered}$$