Question

When a number is decreased by 10% of itself the result is 171. What is the number?

Answer 1

$100\%-10\%=90\%\\\\ \begin{array}{ccc}90\%&-&171\\\\100\%&-&x\end{array}\\\\cross\ multiply\\\\90x=171\times100\\\\90x=17100\ \ \ |divide\ both\ sides\ by\ 90\\\\\boxed{x=190}\leftarrow solution$