A typist typed complete pages of several books in a day. If he typed

Question

A typist typed complete pages of several books in a day. If he typed a total of 600 pages in a day, was the average typing time per page less than 70 secs?

(1) It took at most 50 minutes to type each book.
(2) The total number of books for which he typed that day was 12.

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Purnank · Answer

I think C.
Given - Typist typed total of 600 pages in a day.
1st - It took at most 50 minutes to type each book.
we dont know book count otherwise we could have counted no. of pages per book and hence from there we could check for "the average typing time per page less than 70 secs?"
Not sufficient.

2nd - The total number of books for which he typed that day was 12.
But again this doesnt talk about time required for each book.
Not sufficient.

Combining both 
Avg page count per book = 600/12 = 50
and max time that typist took for 50min. 
50/50 = 1 page per min means 1 page per 60sec.
Sufficient.

siddhantvarma · Answer

The language of this question confused me. Here's what's happening:
The typist typed 600 pages in a day and we need to find if the average typing time per page is less than 70 seconds. In other words, we need to determine if it takes the typist less than 70 seconds to type a single page. Essentially, we need to find the typing rate of the typist or get a sense of the range of the typist's typing rate. 
The missing information in the question is how long did the typist type for in a day? If we knew that he, say worked for 1 hour, or 30 minutes we could divide 600 by the number of minutes he worked for the entire day to get pages/second. Now let's look at the statements:

Statement (1): It took at most 50 minutes to type each book. 
We now know that it takes the typist 50 minutes/book. We know there are total 600 pages. If we know how many books there are, we could solve it using this information. However, Statement 1 simply tells us the typing rate/book, without knowing the number of books we can't determine the typing rate per page.   Insufficient => (A) and (D) are out.

Statement (2): The total number of books for which he typed that day was 12. 
We now know that the 600 pages he typed in the day was for 12 books => average 50 pages per book (600/12). Now we need to know how long did the typist spent on a book on average. We don't know that.   Insufficient => (B) is out.

Both the statements together give us the following info:
Number of books = 12
Total pages = 600
Average page/book = 600/12 = 50 pages/book
Time for a single book = 50 minutes
Time for a single page = 50 pages/50 minutes => 1 page/minute => 1 page in 60 seconds < 70 seconds
  Therefore, both statements together are sufficient (C)

pierjoejoe · Answer

the problem states in statement (1) --> that he "It took at most 50 minutes to type each book". this means that the time to write each book is at most (less than) 3000 seconds.

now statement (2) states that there are 12 books.

taking both statements together we know that there are on average 600/12 pages per book, or 50 pages per book. we also know that the rate at which she wrote each book (50 pages on average) is less than 3000 seconds. this means that the rate at which she wrote each page is 
(50 pages/book)/(3000 seconds/book) = 1page/60 seconds

BUT we also know that 3000 is the maximum value, thus if for example we say that it took (from "It took at most 50 minutes to type each book") 40 minutes for each book --> than 40 * 60 = 2400 seconds for each book. Thus the rate would be 
(50 pages/book)/(2400seconds/book) = 1page/48 seconds

that will always be greater than 1 page every 70 seconds. thus C

arushi118 · Answer

WIll we not be assuming that each book has equal number of pages by doing 600/12? Because nowhere is it given that each book has same pages.

Gmat860sanskar · Answer

No Arushi, here we are not concerned about equal book pages.

Here statement 1 says : "  It took at most 50 minutes to type each book."

so each book is typed within 50 minutes, we just need to know how many books actually are there, and through statement 2, we got to know it's 12 books, then we can infer that maximum time it took writer to type 600 pages is 50 minutes * 12 = 600 minutes.

so maximum rate here will be 1 page per 60 second so we can confidently say that the average typing time per page is less than 70 secs

That's why our answer here is C

axeofflane · Answer

I swear all e-gmat questions are worded this way haha, question wording is not the best!

Adit_ · Answer

I think the question can be worded better like "average typing time considering he stops only after completing all the pages"
From the stem one can assume that breaks may be included, as they mention 600 pages in a day. I could consider the entire day as a whole too and then the time per page is more than 70secs.

IMO it is C if the stem asked:
"Is average typing time greater than 50 secs?"

A typist typed complete pages of several books in a day. If he typed

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A typist typed complete pages of several books in a day. If he typed

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