Answer
$\frac{21}{10}$
Work Step by Step
0.1 is equal to $\frac{10}{100}$. We now must write 2 in terms of a fraction with a denominator of 100. $\frac{200}{100}$ equals 2, so we add $\frac{200}{100}$ and $\frac{10}{100}$ to obtain our answer of $\frac{210}{100}$ (which can be simplfied to $\frac{21}{10}$). Because this number can be written as a fraction, it is rational.
