let's convert the 0.05 to a fraction first, so we have two decimals, so our fraction will have two zeros then.
[tex]\bf 0.\underline{05}\implies \cfrac{005}{1\underline{00}}\implies \cfrac{1}{20} \\\\[-0.35em] ~\dotfill\\\\ 10\div 0.05\implies \cfrac{10}{1}\div \cfrac{1}{20}\implies \cfrac{10}{1}\cdot \cfrac{20}{1}\implies 200[/tex]
