Nov - Feb (4 months): Company produced 4x rakes @ x rakes per month
Mar - Oct (8 months): Company shipped 4x rakes @ x/2 rakes per month
We are interested in the amount stored between Mar-Oct only, since no storage cost incurred between Nov-Feb.
The important point to note in the question here is that the company ships out x/2 rakes at the beginning of each month (from Mar - Oct). So this means, in Mar, the company started off with 3.5x rakes in its storage. And every month, this gradually reduces by x/2. You now have an arithmetic progression for the monthly storage quantities between Mar-Oct.
3.5x 3x 2.5x 2x 1.5x 1x 0.5x 0x
Notice that in October, the number of rakes stored is 0 because the last x/2 rakes were shipped out at the beginning of October.
Summing up the quantities, you get:
Total storage (Mar - Oct)= 3.5x + 3x + 2.5x + 2x + 1.5x + 1x + 0.5x + 0x
= 14x
Total storage cost (Nov - Oct) = 14x*(0.1) = 1.4x
Choose C.
-BM-
