11 9/10 and 3 2/5
\(\left \{ {{ 11\frac{9}{10}+3\frac{2}{5}=15\frac{3}{10}} \atop { 11\frac{9}{10}-3\frac{2}{5}=8\frac{5}{10}}} \right.\)
To solve for this, you can create a series of two equations
\(\left \{ {{y+x=15 \frac{3}{10} } \atop {y-x= 8\frac{5}{10} }} \right.\)
After that, you solve one of the equations for x and plug it into the other equation.
\(\left \{ {{x=15 \frac{3}{10}-y } \atop {y-x= 8\frac{5}{10} }} \right.\)
\({2y-15 \frac{3}{10}= 8\frac{5}{10}\)
Then, solve for variable y
\({2y=23 \frac{8}{10}\)
\({y=11\frac{9}{10}\)
Then, you plug in this value for y into one of the original equations
\(11\frac{9}{10}+x=15 \frac{3}{10}\)
\(x=15 \frac{3}{10} -11\frac{9}{10}\)
\(x=3 \frac{2}{5}\)
