a) The weighted average cost of items in inventory is ...
... (50×$30.50 +70×31.50 +30×33.25 +40×30.75)/(50 +70 +30 +40) ≈ 31.36
so the value of the 75 remaining units is 31.36×75 = $2351.64
b) When the inventory is valued by the FIFO method, the items remaining in inventory are valued at the last amount(s) paid. There are 75 items in inventory so that's all of the August units, all of the June units, and 5 of the 70 March units.
... (40×$30.75 +30×33.25 +5×31.50) = $2385
c) Same as for FIFO, except working from the other direction. The items remaining in inventory are the first ones purchased, so have a value of ...
... (50×$30.50 +25×31.50) = $2312.50
