If 34% of a number is 85,

Let the required number be $\mathrm{x}$. Then, we have :

$(34 \%$ of $\mathrm{x})=85$

$\Rightarrow\left(\mathrm{x} \times \frac{34}{100}\right)=85$

$\Rightarrow \frac{34 \mathrm{x}}{100}=85$

$\Rightarrow \mathrm{x}=\left(85 \times \frac{100}{34}\right)$

$\Rightarrow \mathrm{x}=250$ Hence, the required number is $250 .$