Answer:
 $778.10
Step-by-step explanation:
For computing the ending inventory using the weighted average first we need to compute the average per unit which is shown below:
= (Beginning inventory units × price per unit + purchase inventory units × price per unit + purchase inventory units × price per unit + purchase inventory units × price per unit ) ÷ (Beginning inventory units + purchase inventory units + purchase inventory units + purchase inventory unit) 
= (60 units × $2 + 390 units × $2.50 + 105 units × $2.60 + 55 units × $3) ÷ (60 units + 390 units + 105 units + 55 units) 
= ($120 + $975 + $273 + $165 ) ÷ (610 units) 
= ($1,533) ÷ (610 units) 
= $2.51 
Now the ending inventory is 
= (Total units available - sale units) × average cost per unit 
= (610 units - 300 units) × $2.51
= $778.10