#### Answer

$0.167 \text{ M}$

#### Work Step by Step

Moles of $HNO_3=0.05000\text{ L}*0.100\text{ M}+0.10000\text{ L}*0.200\text{ M}=0.0250\text{ moles}$
Volume of solution = 50.00 mL + 100.00 mL = 150.00 mL = 0.15000 L
Molarity of solution = $\frac{0.0250\text{ moles}}{0.15000 \text{ L}}=0.167 \text{ M}$