Assume a company makes the following purchases $/$ sales:

January $1-$ purchased $10$ units at $$\frac{10}{?}$ unit $-$ total $$100$

January $5-$ purchased $10$ units at $$\frac{20}{?}$ unit $-$ total $$200$

January $10-$ purchased $10$ units at $$\frac{30}{?}$ unit $-$ total $$300$

On January $15-$ they sell $10$ units. What is the cost of goods sold using the LIFO method?