Answer
$\frac{13}{14}$
Work Step by Step
The LCM of the original denominators, 5, 7, and 10, is 70. Therefore, we can rewrite all three fractions with a denominator of 70.
$\frac{3}{7}+\frac{2}{5}+\frac{1}{10}=\frac{3\times10}{7\times10}+\frac{2\times14}{5\times14}+\frac{1\times7}{10\times7}=\frac{30}{70}+\frac{28}{70}+\frac{7}{70}=\frac{30+28+7}{70}=\frac{65}{70}=\frac{13}{14}$