jmc

The most straightforward method would be to calculate both prices, and subtract. But there's a better method... Before we start, it's always good to convert the word problems into expressions, we can solve. So we know that the price of the object after a $6.5\%$ increase will be $20\times 6.5\%$, and the price of it after a $6\%$ increase will be $20\times 6\%$. And what we're trying to find is $6.5\%\times 20-6\%\times 20$, and if you have at least a little experience in the field of algebra, you'll notice that both of the items have a common factor, $20$, and we can factor the expression into $$\begin{array}{rl}(6.5\%-6\%)\times 20& =(.5\%)\times 20\\ & =\frac{.5}{100}\times 20\\ & =\frac{1}{200}\times 20\\ & =.10\end{array}$$ $.10$ is choice $\boxed{\text{textdollar}.10}$