A certain business produced x rakes each month form November through February and shipped ~$\frac{x}{2}$~ 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 $0.10 per rake each month from March through October for the rakes that had not been shipped. In terms of x, what was the total storage cost, in dollars, that the business paid for the rakes for the 12 months form November through October?
0.40x
1.20x
1.40x
1.60x
3.20x
题目没读仔细,还在算MAR-OCT每个月的增量,实际这几个就是卖NOV- FEB的存货
Nov-Feb: Total Prod: 4x
Mar-Oct: Stock: 3.5x, 3x...0.5x,, 0 是a1=0 a8=3.5公差为0.5的等差数列。 求和S=(0+3.5)*/2=14.
所以14x*0.1=1.4x
(3.5+2+2.5+2+1.5+1+0.5)x*0.1=1.4x