Answer:
$935.61
Step-by-step explanation:
Firstly, we need to calculate weighted average inventory cost at every time anchors (purchase - in or sell - out)
At time t = 1, 64 units @ 5 per unit.
At time t = 2, 64 + 110 = 174 units @ (64 x 5 + 110 x 5)/(64 + 110) = 5 per unit.
At time t = 3, 174 - 90 = 84 units @ 5 per unit.
At time t = 4, 84 + 55 = 139 units @ (84 x 5 + 55 x 6)/(84 + 55) = 5.40 per unit.
At time t = 5, 139 - 90 = 49 units @ 5.40 per unit.
Cost of goods sold for the year = 90 x 5 + 90 x 5.40 = $935.61