In June 1990, a small academic press published an initial run of 2,500

In June 1990, a small academic press published an initial run of 2,500 copies of linguist Chloe Vermeulen’s first book, Speech and Speaking. Because the first run was selling well, a second, larger run was produced in June 1995. Total sales for the period from June 1995—June 2000 represented an increase of 52 percent over total sales for the preceding five years; by June 2000, Vermeulen’s book had sold a total of 3,843 copies. In 2000, Speech and Speaking was cited in an influential paper; subsequently, for the period June 2000—June 2005, sales of Vermeulen’s book were double the sales for the previous five-year period.

In the table, identify the number of books that most closely approximates the total sales of Speech and Speaking for each of the five-year periods June 1990 June 1995 and June 2000—June 2005, based on the information given. Make only two selections, one in each column.

June 1990-June 1995	June 2000-June 2005	Total sales for the period (number of books)
		1,320
		1,530
		2,530
		2,640
		3,800
		4,640

There seems to be a lot of useless information here to throw you off guard.

Let's say x books were sold between 1990-1995.

It says in the text "Total sales for the period from 1995-2000 represented an increase of 52 percent over total sales for the preceding five years."

So, 1.52*x books were sold between 1995-2000.

It then also says "For the period of 2000-2005, sales were double the sales for the previous five-year period."

This means, between 2000-2005, 2*(1.52*x) books were sold. (or 3.04*x)

Now look at the answer choices. We need to find x and 3.04x.
If we let x = 1320, then 3.04x should be around 4013, but there's no answer choice around 4013.
Next, let x = 1530. Then 3.04x should be around 4651. Aha! There's a choice for 4640, but let's just make sure there's nothing closer.
If we let x = 2530 (or more) then 3.04x = 7691 (or more), so we can eliminate the rest of the choices.

Thus your answer is 1530 and 4640.

Hope that helped.
_________________

here is how i did it:
let X be sales between 1990-1995, so 1.52x represents sales between 1995-2000.

since by 2000, sales =3843, that means x+1.52x=3843, solve for x =1525

1.52*1525=2318, and double 2318 we get 4636

I think this way 2000-2005 years /1990-1995 years =1.52*2=3.04
if we divide 4640 to 1530 we get that approx. 3.04
right?

do you have any other thoughts how to solve it?
_________________

Hi,
This is how I arrived at the answers:-
Let the sales for the period 1990-95 be 'x'
Therefore, the sales for the period 1995-2000 is '1.52x'
Now, total sales for the period is 'x+1.52x=2.52x=3843'
Solving we get x=1525.
Since the question asks for the closest approximation we can approximate the value of x to 1530.
Therefore, sales for the period 1990-95 is 1530 (after closest approximation)
and, sales for the period 1995-2000 is 2318.
Hence, the sales for the period 2000-05 is 2x2318=4636 which after approximation would be 4640.
hope it helps.

No worries guys, you'll have access to the on-screen calculator for the Integrated Reasoning section of the exam. At times, you may want to use the calculator to do some real-world calculations quickly. Weird decimals or percentages are fair game on the IR section.

Hi All,

This prompt is more about organization and basic arithmetic than anything else. You do NOT need the calculator as long as you take good notes, make some reasonable estimates and do some multiplication.

From the information in the prompt, we can make a little table of data (based around three 5-year 'blocks' of time):

'90-'95: 2500 books published; X books sold
'95-'00: >2500 published; 1.52X books sold

Total books sold '90-'00 = 3843 = 2.52X

From here, you should quickly note that X MUST be > 1,000. A reasonable estimate would be X = 1500 (try multiplying 2.5 by 1500 and you'll see).

'00-'05: 2(1.52X) books sold = 3.04X books sold

The question asks for TOTAL BOOKS SOLD from '90 - '95 and from '00-'05

Using X = 1500 as an estimate....
'90-'95 = X = 1500 books sold

'00-'05 = 3.04X = about 4500 books sold

From the given values in the table, the only answers that are close are:

GMAT assassins aren't born, they're made,
Rich

in period 190-1995 , the number sold is x
in 1995-2000, the number is 1.5 x

x+1.5x= 3.8
x=1.5
1.5x=2.3

the periond 2000-2005 is doble of 2.3 so, it is 4.6

the correct is

1.5 and 4.6

There is no use to do tedious calculations, The GMAT way is to approximations.

let the sale done in 1990-95 period be x

Since the sales for period 1995-2000 increased by 52% over the previous 5 year period, then we can approximate it as 50% increase.

Therefore, x+1.5x= 4000 ( approximating 3843 to 4000)

2.5x= 4000

x= 4000/2.5 = 1600

The number closest to 1600 is 1530, so that's the correct answer.

Also 1.5x = 2400( from above)

Sales for 2005-05 period is doubled over previous period

Therefore sales for 2000-05 period = 2 * 2400 = 4800

4640 is the option closest to 4800, hence that is the correct ans.

You can easily do all this calculations in your head in matter of 2 minutes but only if you approximate.

Dear,
Thanks for the explanation. I was just lost before I read this post. But the information "that 2500 copies were published in 1990" is useless for this problem?

Thanks!
Regards
Andy

Yes, you have not been given any information from this statement how many of those 2500 books were actually sold. But in the next line it is mentioned that 50% more books were sold from 95-2000 and that the total till 2000 was 3843 books.

So, you can setup the equations like this:

Let books sold in 90-95 = x ---> books sold from 95-2000 = 1.52x (as it is 52% more)

Thus x+1.52x = 3843 ----> x=1525 books.

Also given is that during the period 2000-2005, twice the number of books sold in the period 95-2000 were sold. Thus books sold in 2000-05 period = 2*1.52x = 3x = 4636 books.

Thus you have the 2 answers.
_________________

I took a bit of a different approach.
It said that in 1990 it made 2500 books and did not make any more until 1995.
So this means, in 1990-1995, they could have sold at most 2,500 books.
This means that for the first column, the answer MUST be 1320 OR 1530

I first tried 1320, to get the value in 1995-2000, I did 1320 * 1.52 = 2006
Then to get the 2000-2005 value, I did 2 * 2006 = 4012.
3960 is not an answer choice for the second column, I now drop my answer of 1320 for column 1

I then tried 1530, to get the value in 1995-2000, I did 1530 * 1.52 = 2326
Then to get the 2000-2005 value, I did 2 * 2326 = 4651
Yay, 4651 matches an answer in column 2

This means the answer is 1530 and 4640

WARNING: this worked because we were able to rule out one of the 2 possibilities. It is possible that GMAT creates 2 pairs that work in proportion but NOT in true value (that is, having 2 pairs that work through the workflow I went through).