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Manager
Joined: 29 Apr 2017
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Location: India
Concentration: Operations, Other
GMAT 1: 660 Q43 V38
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WE: Operations (Transportation)

Re: A store sells apples in pack of 6, 9, or 20. By ordering 2 packs of 6
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26 Jul 2019, 23:52
To find: which option is the greatest no. of apples that can't be bought in packs of 6, 9 or 20? Solution: A) 43 we can't buy 43 apples as its not divisible by either 6, 9,20 or combination of any 43/6=7 packs +1 apple 43/9=4 packs of 9+7 apples=4 packs of 9+1 pack of 6+1 apple 43/20=2 packs of 20+3 apples B) 44 we can't buy 45 apples as well 44/6=7 packs of 6+2 apples 44/9=4 packs of 9 + 8 apples=4 packs of 9+1 pack of 6+2 apples 44/20=2 packs of 20+4 apples C) 45 we can buy 45 apples as 45/9=5 packs of 9 D) 46we can buy 46 apples as 46/20=2 packs of 20 + 6 apples=2 packs of 20+1 pack of 6 E) 47 we can't buy 47 apples as well 47/6=7 packs of 6+5 apples 47/9=5 packs of 9+2 apples 47/20=2 packs of 20+7 apples=2 packs of 20+1 pack of 6+1 apple
So, greatest no. of apples that can't be bought is 47.
Alternatively, one may start with the biggest number in the options and will find that option to be the answer.
Answer: E



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Re: A store sells apples in pack of 6, 9, or 20. By ordering 2 packs of 6
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27 Jul 2019, 02:50
A store sells apples in pack of 6, 9, or 20. By buying 2 packs of 6, you can get 12. But you cannot buy 13 apples, since no combination of 6, 9, and 20 adds up to 13. What is the greatest number of apples that you CANNOT buy in the store?
By looking at answer choices we need to find the greatest number which does not satisfy the eq. N = 6a+9b+20c (where a, b, c >=0).
Now, 44 = 6*4 + 20*1 45 = 9*5 47 = 9*3 + 20*1
Both, 43 and 46 doesn't fit the combination of 6, 9 and 20. and greatest of both is 46. Hence, answer = 46.
A. 43 B. 44 C. 45 D. 46 E. 47
Answer Choice: D



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Re: A store sells apples in pack of 6, 9, or 20. By ordering 2 packs of 6
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27 Jul 2019, 04:36
A. 43  B. 446*4 +20 C. 459*5 D. 46 E. 47 20+9*3



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Re: A store sells apples in pack of 6, 9, or 20. By ordering 2 packs of 6
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27 Jul 2019, 06:44
A store sells apples in pack of 6, 9, or 20. By buying 2 packs of 6, you can get 12. But you cannot buy 13 apples, since no combination of 6, 9, and 20 adds up to 13. What is the greatest number of apples that you CANNOT buy in the store?
A. 43 B. 44 C. 45 D. 46 E. 47
Lets start with highest number in the option 47. It can be bought. 1 pack of 20 and 3 packs of 9. 46 cannot be bought  hence answer is D



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Joined: 23 May 2019
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Re: A store sells apples in pack of 6, 9, or 20. By ordering 2 packs of 6
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04 Dec 2019, 04:06
Prasannathawait wrote: we cannot have 43 and 47. 47 is the largest. E is the answer. E option is not correct as: 47=20*1+9*3 Among the given numbers, only 43 is not possible to be obtained from any combination




Re: A store sells apples in pack of 6, 9, or 20. By ordering 2 packs of 6
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04 Dec 2019, 04:06



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