OG_IR_Q3 求讨论

shl020

求助IR第一个大题（多源推理）的第3题，就是: Let X denote the block rate of the host hotel for a particular conference, and let Y denote the lowest room rate available in the host hotel outside of the conference block. For a conference that requires a two-night hotel stay, which one of the following expressions represents the least amount of discount on the conference registration fee...

OG的思路是：2个晚上的savings就是2(X-Y), 所以discount只要等于X-Y就能吸引客户。
我的问题是，客人的每个不同方案不应该是registration fee (RF) 或者discounted registration fee (DRF) 加上住宿费吗？为什么不算registration fee进去呢？否则就应该是discount应该大于等于 (RF+2Y) - (DRF+2X).


因为肯定要按照OG的思路来么，我就是想求助到底是我哪个部分想错了，或者miss掉什么信息呢？谢谢！

dcsuperman

亲，你没发现你等式左右都有DRF么？展开后你就会HLL的发现····

shl020

呃呃，抱歉还是没懂。我把我的问题写详细点哈，麻烦看下：原文P3说：
(1) ...by increasing the conference registration fee by a fixed amount and then offering an equivalent registration fee discount to attendees who book rooms in the block.
所以得出"a fixed amount" = "an equivalent registration fee discount" = RF-DRF
(2) A study has shown that if this registration discount is equal to at least half the potential savings of...strategy则可以deter attendees...
所以得出 (1)中的"an equivalent registration fee discount", 即 RF-DRF>=1/2savings可以deter attendees...
所以RF-DRF>=1/2[(DRF+2x)-(RF+2y)]
=>  RF-DRF>=1/2(DRF-RF)+(x-y)
=>  3/2 (RF-DRF)>=(x-y)
所以RF-DRF要至少等于2/3(x-y)...@@所以到底是哪个地方的理解错咧？

annielucky

为啥savings里不考虑registration fee的差别呢？

stella1220

你的分析：(1) ...by increasing the conference registration fee by a fixed amount and then offering an equivalent registration fee discountto attendees who book rooms in the block.
所以得出"a fixed amount" = "an equivalent registration fee discount" = RF-DRF
(2) A study has shown that if this registration discount is equal to at least half the potential savings of...strategy则可以deter attendees...
所以得出 (1)中的"an equivalent registration fee discount", 即 RF-DRF>=1/2savings可以deter attendees...
直到这里都是对的，下面的则个不等式就出问题了。关键在于：原文Article的第9-16行描述了参加会议的人会使用ROHH strategy和ROB strategy来avoid extra cost of reserving a room within the block at the host hotel（避免多付旅馆的钱），这里的两个策略都没有涉及到registration fee，采用这两个strategy得到的savings与registration fee的打折多少无关。之后文章23-25行说的...is equal to at least half the potential savings of an attendee's particular cost saving strategy,...说明了这里的savings＝2(X－Y)。你下面的不等式把会费也算进去了，所以不对。
所以RF-DRF>=1/2[(DRF+2x)-(RF+2y)]
=>  RF-DRF>=1/2(DRF-RF)+(x-y)
=>  3/2 (RF-DRF)>=(x-y)
所以RF-DRF要至少等于2/3(x-y)...@@所以到底是哪个地方的理解错咧？

hehanbo

我一直想问，两晚都打折才能吸引啊，为什么要除2，算一天的就吸引人了？