DeepikaV wrote:

hello,

if we consider total mail be 100( <2 days & >3 days =100) then ' most mail arrives 3 or more business days after being sent" with number= 51( as most can be 51-100) and

few mails arrive within 2 business days= 49 ( few range is 1-49). so, mails that arrive within 2 business days are correctly addressed without damage(total 49) and mails that arrive 3 or more days can be correctly addressed with damage and not correctly addressed( 50 can be not correctly addressed and one can be correctly addressed with damage or viceversa) . so, we cannot conclude that large proportion can be incorrectly addressed(D)

please explain if my logic is wrong. i have selected answer as C

Dear

DeepikaV,

I'm happy to respond.

First of all, notice that this is a "

must be true" question. We can construct scenarios in which (C) is true, but we also can construct scenarios in which (C) is false. That's why (C) doesn't work.

Now, you have propose to have constructed an argument that disproves (D), but think about it. Here is (D):

(D) A large proportion of mail is incorrectly addressed.Your symbolic representation is a bit unclear, so I will translate what you say into clear symbols.

P = correctly addressed mail

Within this category,

P1 = correctly addressed, undamaged = arrives in two days or less

P2 = correctly addressed, damaged = arrives later

Notice that "

nearly all" of P is P1, so P2 is very small.

Q = incorrectly addressed = arrives later

Let's say P = 51%, with P1 = 49% and P2 = 2%. Even this makes P2 bigger than the words seem to suggest, because P1 is supposed to be "

nearly all" of P. That would leave us with Q = 49%. Thus, a majority (P2 + Q - 51%) would arrive late.

The trouble is, (D) does not claim that Q is a

majority, but only a

large proportion. A third, 1/3 of the population, is a large proportion, especially for something that is a clear mistake. Thus, 49% would definitely be a large proportion.

If 10% of car trips resulted in accidents, that would be huge proportion. If 10% of all air flights resulted in crashes, that would be a gigantic proportion. If 5% of people who underwent surgery died, that would a gargantuan proportion. Those are more extreme cases. If 1/3 of the words that a person wrote were misspelled, that would be a large proportion. If a certain dishwasher broke 1/3 of the dishes he washed, that would be a huge proportion. If a certain person, after tying his shoes, found that his laces soon after needed to be retied 1/3 of the time, that would be a large proportion. Those are more ordinary scenarios.

Much in the same way, every individual and every business that sends mail wants to address that mail correctly. If even 1/3 of them are not addressing them correctly, that is a very large failure rate on what should be a simple task. Thus, 49% is a large proportion.

Does this make sense?

Mike

_________________

Mike McGarry

Magoosh Test PrepEducation is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939)