GMAT ques - pls help

[geet_ge]

A certain business produced x rakes each month from November through February and shipped x/2 rakes at the beginning of each month from March through October. The business paid no storage costs for the rakes from November through February, but it paid storage costs of $.10 per rake each month from March through October for the rakes that that had not been shipped. Inters of x, what was the total storage, in dollars, that the business paid for the rakes for 12 months from Nov through Oct?

Ans - 1.4x

[WhiteWNNoise]

[Anurag@Gurome]

A certain business produced x rakes each month from November through February and shipped x/2 rakes at the beginning of each month from March through October. The business paid no storage costs for the rakes from November through February, but it paid storage costs of $.10 per rake each month from March through October for the rakes that that had not been shipped. Inters of x, what was the total storage, in dollars, that the business paid for the rakes for 12 months from Nov through Oct?

Ans - 1.4x

Let us take x = 2 to make calculations simpler.
Then the total number of rakes produced from Nov to Feb = 2 * 4 = 8
Storage costs for 8 months between March and October = 0.1 * (7 + 6 + 5 + 4 + 3 + 2 + 1) = 2.8
From the given answer choices, when we multiply each by x = 2 to get 2.8, only answer choice C gives the desired result.

The correct answer is C.