9/10 divided by (1/10 plus 2/5)

1.8 is the answer 1/10+2/5 is equal to 0.5 That divided by 9/10 is 1.8 or 1 8/10

[latex]oxed{ frac{ frac{9}{10} }{( frac{1}{10} + frac{2}{5} )} = frac{ frac{9}{10} }{ frac{1}{2} } = frac{9}{10} . frac{2}{1} = frac{18^{div2}}{10^{div2}} ~ o~oxed{ frac{9}{5}} }[/latex]