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A farmer spent $35 on feed for chickens and goats. He spent [#permalink] ### Show Tags 21 Apr 2012, 09:03 3 This post was BOOKMARKED 00:00 Difficulty: 15% (low) Question Stats: 83% (02:52) correct 17% (02:25) wrong based on 171 sessions ### HideShow timer Statistics A farmer spent$35 on feed for chickens and goats. He spent 40% money on chicken feed, which he bought at a 20% discount off the full price, and spent the rest on goat feed, which he bought at full price. If the farmer had paid full price for both the chicken feed and the goat feed, what amount would he have spent on the chicken feed and goat feed combined?

A. $37.80 B.$38.50
C. $39.20 D.$39.50
E. $40.60 I set up the equation as follows: (C for chicken feed and G for goat feed) 0.8x0.4xC + 0.6G =35---a 0.4C+0.6G=35+?----b equation b is 8% greater than a so I multiplied 35 by 8%, getting$2.8. Thus, I selected 37.8 but the answer is 38.50.
Q: could anyone please kindly point out what went wrong here?

The OA explanation is as follows but I can't understand the part in bold
0.4($35)=F (full price of chicken feed)$14=0.8F

$17.5=F Total paid = 17.5+35(0.6)=38.50 Q: how can 14=F and then change to 14=0.8F? Many thanks!! [Reveal] Spoiler: OA Math Expert Joined: 02 Sep 2009 Posts: 36548 Followers: 7077 Kudos [?]: 93123 [1] , given: 10552 Re: A farmer spent$35 on feed for chickens and goats. He spent [#permalink]

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21 Apr 2012, 10:41
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Welcome to GMAT Club. Below is a solution for your question.

A farmer spent $35 on feed for chickens and goats. He spent 40% money on chicken feed, which he bought at a 20% discount off the full price, and spent the rest on goat feed, which he bought at full price. If the farmer had paid full price for both the chicken feed and the goat feed, what amount would he have spent on the chicken feed and goat feed combined? A.$37.80
B. $38.50 C.$39.20
D. $39.50 E.$40.60

A farmer spent 40% money on chicken feed, so he spent 0.4*$35=$14 on chicken feed, thus he spent the remaining 35-14=$21 on goat feed. Now, since he bought chicken feed at a 20% discount then the original price of it was x*0.8=$14 --> x=$17.5. Therefore if the farmer had paid full price for both the chicken feed and the goat feed, then he would he have spent 17.5+21=$38.5.

Hope it's clear.
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21 Apr 2012, 14:39
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lamania wrote:
Thank you very much Bunuel. It is clear now and the OA explanation must have a typo then.
However, why can't I put the 80% (20% discount) in the equation in the first place but rather have to get the 40% portion first and then obtain the before-discount price? The right approach makes great sense but if I'm faced with similar questions, I may set up the equation by incorporating all the factors again although that won't lead to the right answer.

You can write one equation right away I just broke down the solution into several steps to make it easier. If interested here it is: 0.4*35/0.8+0.6*35=38.5. Notice that you should divide 0.4*35 by 0.8 to get original price and not multiply.
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22 Apr 2012, 08:56
guys here is an easier way:
Let the farmer had 100 to spend.
He spent 40 on chickens and 60 on goats.
now actual price of chicken feed without discount
x-20%x=40
0.8x=40 or x=50
So without discount he would have spent 50+60=110
Now 110 for 100
For 35 it is 110/100*35=38.5

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08 Jul 2016, 04:09
lamania wrote:
A farmer spent $35 on feed for chickens and goats. He spent 40% money on chicken feed, which he bought at a 20% discount off the full price, and spent the rest on goat feed, which he bought at full price. If the farmer had paid full price for both the chicken feed and the goat feed, what amount would he have spent on the chicken feed and goat feed combined? A.$37.80
B. $38.50 C.$39.20
D. $39.50 E.$40.60

He spent 40% of 35 on chicken feed, i.e 35*40/100= 14

This $14 was 80% (He got 20% discount), So the actual price without discount was= 14*100/80= 17.5 Amount spent on goat feed= 35-14= 21 Total price without discount= 21+17.5= 38.5 B is the answer _________________ I welcome critical analysis of my post!! That will help me reach 700+ Senior Manager Status: Exam scheduled!! Joined: 05 Sep 2016 Posts: 411 Location: United States (WI) Concentration: Marketing, Technology WE: Other (Law) Followers: 3 Kudos [?]: 13 [0], given: 241 Re: A farmer spent$35 on feed for chickens and goats. He spent [#permalink]

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18 Oct 2016, 12:01
We know 60% of $35 was spent on goats, leaving us with$14 spent on chickens.

$14 spent was with discount -->$14 = x-0.20x --> 14 = 0.80x --> x = $17.5 (original price)$17.5+$21 =$38.5