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At a certain bakery, each roll costs r cents and each [#permalink]
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18 Dec 2005, 17:08
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At a certain bakery, each roll costs r cents and each doughnut costs d cents. If Alfredo bought rolls and doughnuts at the bakery, how many cents did he pay for each roll? (1) Alfredo paid $5.00 for 8 rolls and 6 doughnuts (2) Alfredo would have paid $ 10.00 if he had bought 16 rolls and 12 doughnuts
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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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18 Dec 2005, 17:11
This is a typical GMAT trap. YOu might have seen my earlier post about picking numbers for DS. In general, two equations in two unknowns can be solved to get a unique (one) solution except when the two equations are the same. If you divide the information in statement 2, you get statemetn 1. So, statemetn 2 is not giving you any new information. Hence, the answer should be E.
Srinivas (mathguru).



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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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18 Dec 2005, 18:28
The oa is E
thanks srinivasssrk, i fell for it.



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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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18 Dec 2005, 19:28
Yup answer is E.
(1) and (2) are the same thing
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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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18 Dec 2005, 19:35
TeHCM wrote: Yup answer is E.
(1) and (2) are the same thing
For once, I get the right answer..



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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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19 Dec 2005, 00:51
joemama142000 wrote: At a certain bakery, each roll costs r cents and each doughnut costs d cents. If Alfredo bought rolls and doughnuts at the bakery, how many cents did he pay for each roll?
1) Alfredo paid $5.00 for 8 rolls and 6 doughnuts
2) Alfredo would have paid $ 10.00 if he had bought 16 rolls and 12 doughnuts
From stmt1 we get 8r+6d = 5
From stmt2 we get 16r + 12d = 10
Stmt1 * 2 = stmt 2, and we will not be able to solve this equen. So my answer is E.



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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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19 Dec 2005, 10:44
Similar Equations , hence 1 equation , 2 variables .... E



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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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03 Jan 2015, 09:42
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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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05 Jan 2015, 03:12
At a certain bakery, each roll costs r cents and each doughnut costs d cents. If Alfredo bought rolls and doughnuts at the bakery, how many cents did he pay for each roll? Let \(r\) be the price of rolls in cents and \(d\) be the price of doughnuts in cents. Note that \(r\) and \(d\) must be an integers. Q: \(r=?\) (1) Alfredo paid $5.00 for 8 rolls and 6 doughnuts > \(8r+6d=500\) > \(4r+3d=250\). Multiple solutions are possible, for instance: \(r=25\) and \(d=50\) OR \(r=10\) and \(d=70\). Not sufficient. (2) Alfredo would have paid $ 10.00 if he had bought 16 rolls and 12 doughnuts > \(16r+12d=1000\) > \(4r+3d=250\). The same. Not sufficient. (1)+(2) No new info. Not sufficient. Answer: E. Check similar questions here: ctrapquestions177044.html
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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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06 Sep 2016, 22:44
Statement 1: 8r+6d=500 (Dollars to cents). Multiple values of r & d can work. For ex: r=10,d=70 & r=40, d=30. Not sufficient. Statement 2: This is a tautological statement. (As St:1 is multiplied by 2).
Hence, option E.



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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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08 Feb 2017, 20:26
cost of each roll=r cents cost of each doughnut=d cents statement 1: 8r+6d=500 We have only one equation and 2 unknowns Insufficient statement 2: 16r+12d=1000 8r+6d=500( dividing by 2 throughout) This is nothing but the same equation in statement 1.. Insufficient Combining both the statements we have a single equation 8r+6d=500 and 2 unknowns...Hence the value of r cannot be determined The ans is clearly E.
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Re: At a certain bakery, each roll costs r cents and each [#permalink]
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13 Feb 2017, 11:02
Experts, is there a FAST way to detect if we are dealing with that situation (I don't remember the name) when we have 2 variables and it seems INSUF, but them there is only one combo of numbers that makes the equation possible, so it is SUF? How can we quickly check if that is the case? Here I was indecisive between D and E.




Re: At a certain bakery, each roll costs r cents and each
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13 Feb 2017, 11:02






