Problem Solving

Hi,

I can't seem to find this problem on the board so could you please help me sove it? This problem is from the GMAT Prep Software

Rates for having a manuscript typed at a certain typing service are $5 per page for the first time a page is typed and $3 per page each time a page is revised. If a certain manuscript has 100 pages, of which 40 were revised once, 10 ere revised twice, and the rest required no revisions, what was the total cost of having the manscript typed?

A - $430
B - $620
C - $650
D - $680
E - $770

answer d

Ha! I just figured it out while typing it in. So I will leave it for the next person looking for it.
My process
$5 x 100 = $500
$3 x 40 = $120
$3 x 10 = $30 (first revision)
$3 x 10 = $30 (second revision) <--- this is what got me.

anthony.j wrote:Hi,

I can't seem to find this problem on the board so could you please help me sove it? This problem is from the GMAT Prep Software

Rates for having a manuscript typed at a certain typing service are $5 per page for the first time a page is typed and $3 per page each time a page is revised. If a certain manuscript has 100 pages, of which 40 were revised once, 10 ere revised twice, and the rest required no revisions, what was the total cost of having the manscript typed?

A - $430
B - $620
C - $650
D - $680
E - $770

answer d

Ha! I just figured it out while typing it in. So I will leave it for the next person looking for it.
My process
$5 x 100 = $500
$3 x 40 = $120
$3 x 10 = $30 (first revision)
$3 x 10 = $30 (second revision) <--- this is what got me.

Hi,

The mistake that you are doing here is that even those 40 pages and 10 pages which are revised once and twice respectively must be typed first. So you have to add 5$ in addition to the revision cost.

So here we go...

50 pages ---only typing cost 50 x 5 = 250 $

40 pages..type + revision cost 40 x 8 = 320 $

10 pages type + twice revision cost 10 x 11 = 110 $

Hence the total cost = 250 + 320 + 110 = 680 $

Hi Sureshbala,

Thanks for your response. Would it matter that I read the problem as having 100 pages and you read the problem as have 50 pages plus the additional rewrite pages?

I also ran into a problem here. My reason for missing this is that I thought the pages that were revised twice were included in the 40 that were revised once. The problem doesn't make it especially clear that there is a unique set of pages that was revised once, and an entirely different set that was revised twice.

so the totals would be
100*5 for typing
40*3 (first round revisions)
10*3 (second round revisions)
=650, which is incorrect.

Can anyone provide a reason why it would be clear that a page that was revised twice does not count in the 40 that were revised once?

EDIT: The original problem in powerprep does include the keyword "only once"... so there's my answer. Doh!

anthony.j wrote:Hi Sureshbala,

Thanks for your response. Would it matter that I read the problem as having 100 pages and you read the problem as have 50 pages plus the additional rewrite pages?

Well for that approach you'll have to consider 60 pages to be reviewed instead of 50 since ten are revised twice

Cant help that. I think language is ambiguous.

akshaydhande wrote:Cant help that. I think language is ambiguous.

I think it's OK here: "once" = 1, not ≥ 1, etc.