GWD-5-11、28 XDJM 急！

lindaaniu

Q11:
A certain business produced x rakes each month form 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 $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?

A.    0.40x
B.    1.20x
C.    1.40x
D.    1.60x
E.    3.20x
Answer: C

Q28:
Last Sunday a certain store sold copies of Newspaper A for $1.00 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day.  If r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper A, which of the following expresses r in terms of p?

A.    100p / (125 – p)
B.    150p / (250 – p)
C.    300p / (375 – p)
D.    400p / (500 – p)
E.    500p / (625 – p)
Answer: D

lindaaniu

自己顶起来！欢迎大家来讨论

kukumalu1989

11月到2月只生产不运输不付费，三月开始就只运输不生产。所以到三月初的时候总量是4x，三月开始每月初开始运走，就是说3月还有库存3.5x，四月有3x，以此类推，到10月初运走最后的0.5x后，十月的库存量是0也就是说10月不用再付费了。所以这十二个月的库存量就是一个等差数列，和就是（3.5+3+2.5+…0）*7/2=14，再乘以单位cost 0.1就是答案了

28
可以设销售量分别是x和y 可以有两个式子：x=p%（x+y），x=r%（x+1.25y）
我觉得lz是不是把percent那个百分号给忘了
然后把第一个式子变换成x/y=p%/(1-p%),第二个式子变成x/y=r%(x/y+1.25)
把第一个式子代入第二个就可以了