Bob and his 36 items

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Bob and his 36 items

by Woozler » Wed Dec 08, 2010 2:44 pm
If Bob produced 36 or fewer items in a week, he is paid x dollars per item. If Bob produces more than 36 items in a week, he is paid x dollars per item for the first 36 items and 1.5 times that amount for each additional item. How many items did Bob produce last week?

(1) Last week Bob was paid a total of $480 for the items he produced that week
(2) This week Bob produced 2 items more than last week and was paid a total of $510 for the items he produced this week
Source: — Data Sufficiency |

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by Night reader » Wed Dec 08, 2010 5:25 pm
Woozler wrote:If Bob produced 36 or fewer items in a week, he is paid x dollars per item. If Bob produces more than 36 items in a week, he is paid x dollars per item for the first 36 items and 1.5 times that amount for each additional item. How many items did Bob produce last week?

(1) Last week Bob was paid a total of $480 for the items he produced that week
(2) This week Bob produced 2 items more than last week and was paid a total of $510 for the items he produced this week
IOM C .... 44 units

Bob produced =< 36 price x
Bob produced (Y) > 36 price 1.5x

st(1) 480 = 36x + 1,5x*Y where Y is quantity last week >36 => two variables one equation => multiple options on the number line. Not sufficient

st(2) 510 = 36x + 1.5x*(Y+2) since Y is two more than last week => two variables one equation => multiple options on the number line. Not sufficient

Combining st(1&2) => 510-480=30 => two units are at $30 <=> 1 unit @ $15
test for Y =<36

15*36=540 and this is more than 480 => Y must be more than 36 => 1 unit for Y=<36 is equal 15/1.5=$10
36*10 =360 satisfies for $480 amount => find Y>36 ..... 480-360=120 => 120/15=8 (units)
8+36=44 units

Answer 44 units were produced last year.

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by Woozler » Wed Dec 08, 2010 11:12 pm
Oh, God, it's so obvious. It's apalling what mental blocks my brain is capable of creating. $15 and $10 both work, of course, yet I completely ignored the possibility of $10. I'm so not getting 50 on the quant section. Sigh.

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by Night reader » Wed Dec 08, 2010 11:32 pm
Woozler wrote:Oh, God, it's so obvious. It's apalling what mental blocks my brain is capable of creating. $15 and $10 both work, of course, yet I completely ignored the possibility of $10. I'm so not getting 50 on the quant section. Sigh.
relax and study: three months ago I finished all math series of MGMAT and scored 28 in GMAT prep. I had sent all to hell until I got 31 correct in my last GMAT prep session for the quant.

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by gmatmachoman » Thu Dec 09, 2010 1:24 am

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by Night reader » Thu Dec 09, 2010 3:50 am
gmatmachoman wrote:https://www.beatthegmat.com/bob-gmatprep ... 56725.html


It [spoiler]will E and not C!![/spoiler]
after reading the post, I see that we may not even set equation with 36x, for we don't know exactly how many units were produced last week.

it's E

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by Woozler » Thu Dec 09, 2010 8:12 am
Well, I'm relieved at least that it's considered a 700-level problem, at least by the creators of the 198 700-level questions from GMAT prep I.

It's so ridiculously simple once you realize all that's holding you back is a mental block/conviction that $15 MUST be the regular price (or, in the case of the guy who asked the same question back in April, comically enough, who thought that $15 MUST be the "overtime" price). Both, of course, work, so the problem is unsolveable.

By the way, the more I torture GMAT prep 1, the more I come to realize just how little math there is in tougher questions on quant. It's more about quickly catching various nuances and possibilities.

And high-30's to mid/high-40's problems are all middle school math that tests barely anything other than speed (with reasonable accuracy, of course).

Perhaps that's why an engineering degree is no guarantee of a high score on quant.