December 10, 2018 December 10, 2018 10:00 PM PST 11:00 PM PST Practice the one most important Quant section  Integer properties, and rapidly improve your skills. December 11, 2018 December 11, 2018 09:00 PM EST 10:00 PM EST Strategies and techniques for approaching featured GMAT topics. December 11 at 9 PM EST.
Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 02 Dec 2012
Posts: 177

At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
06 Dec 2012, 03:17
Question Stats:
75% (00:59) correct 25% (01:13) wrong based on 1325 sessions
HideShow timer Statistics
At a bakery, all donuts are priced equally and all bagels are priced equally. What is the total price of 5 donuts and 3 bagels at the bakery? (1) At the bakery, the total price of 10 donuts and 6 bagels is $12.90. (2) At the bakery, the price of a donut is $0.15 less than the price of a bagel.
Official Answer and Stats are available only to registered users. Register/ Login.




Math Expert
Joined: 02 Sep 2009
Posts: 51071

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
06 Dec 2012, 03:22




Intern
Joined: 14 Sep 2015
Posts: 9

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
19 Sep 2015, 13:49
I found the answer using both of the statements.
1) 10d + 5b = 12.90 2) d = b  0.15 10(b0.15)+6b=12.90 10b1.5+6b=12.90 16b=14.4 b=0.9 [substitute for b in 2nd equation] d=0.90.15=0.75 5(0.75)+3(0.9)=6.45, which is equal to 12.90(0.5)




VP
Joined: 02 Jul 2012
Posts: 1178
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
06 Dec 2012, 03:23
Question asks for value of 5D + 3B. 1)10D + 6B = 12.9 5D + 3B = 12.9/2. Sufficient 2)We only have D = B  0.15. Even after substitution of this in 5D + 3B we still have an unknown. Insufficient. Answer is A.
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Board of Directors
Joined: 01 Sep 2010
Posts: 3294

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
06 Dec 2012, 03:42



Manager
Joined: 12 Jan 2013
Posts: 155

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
10 Jan 2014, 08:17
Walkabout wrote: At a bakery, all donuts are priced equally and all bagels are priced equally. What is the total price of 5 donuts and 3 bagels at the bakery?
(1) At the bakery, the total price of 10 donuts and 6 bagels is $12.90. (2) At the bakery, the price of a donut is $0.15 less than the price of a bagel. We are given 5*D + 3*B = TC, so what's TC? 1) Look carefully: This simply tells us what 2TC is, so in other words it tells us what 2(5*D + 3*B) is. just take half the result and you've solved the question. 2) This tells us that 5*(B  0.15) + 3*B = TC, but we have two unknowns and one equation, so 2 is not sufficient. We go with A.



Intern
Joined: 10 Jul 2014
Posts: 3

Donut and bagel at bakery question
[#permalink]
Show Tags
10 Jul 2014, 09:10
At a bakery, all donuts are priced equally and all bagels are priced equally. What is the total price of 5 donuts and 3 bagels at the bakery?
(1) At the bakery, the total price of 10 donuts and 6 bagels is $12.90
(2) At the bakery, the price of a donut is $0.15 less than the price of a bagel.
I understand 1) is sufficient. But I'm not understanding why 2) is insufficient. If you let price of donut be x, then price of bagel is x+0.15. Therefore 10x + 6(x + 0.15) = 12.90. Solve that and get a value for x and obviously x + 0.15.
Am I missing something obvious?



Math Expert
Joined: 02 Sep 2009
Posts: 51071

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
10 Jul 2014, 09:13



Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4277
Location: United States (CA)

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
11 Oct 2016, 15:50
Walkabout wrote: At a bakery, all donuts are priced equally and all bagels are priced equally. What is the total price of 5 donuts and 3 bagels at the bakery?
(1) At the bakery, the total price of 10 donuts and 6 bagels is $12.90. (2) At the bakery, the price of a donut is $0.15 less than the price of a bagel. We are given that all donuts are priced equally and all bagels are priced equally and need to determine the total price of 5 donuts and 3 bagels. Let’s start by defining some variables. D = the price per donut B = the price per bagel Thus we need to determine: 5D + 3B = ? Statement One Alone: At the bakery, the total price of 10 donuts and 6 bagels is $12.90. Using the information in statement one, we can create the following equation: 10D + 6B = 12.90 We can simplify the equation by dividing the entire equation by 2. 5D + 3B = 6.45 Thus, the price for 5 donuts and 3 bagels is $6.45. Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E. Statement Two Alone: At the bakery, the price of a donut is $0.15 less than the price of a bagel. We can express D in terms of B: D = B  0.15 Substituting B – 0.15 for D, we get: 5(B – 0.15) + 3B 5B – 0.75 + 3B 8B – 0.75 However, without knowing anything about the price of either D or B, or the total amount spent, we cannot determine the sum of 5D + 3B. Thus, statement two is insufficient. The answer is A.
_________________
Scott WoodburyStewart
Founder and CEO
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions



Manager
Joined: 11 Jul 2016
Posts: 80

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
20 Nov 2016, 04:48
ScottTargetTestPrep wrote: Walkabout wrote: At a bakery, all donuts are priced equally and all bagels are priced equally. What is the total price of 5 donuts and 3 bagels at the bakery?
(1) At the bakery, the total price of 10 donuts and 6 bagels is $12.90. (2) At the bakery, the price of a donut is $0.15 less than the price of a bagel. We are given that all donuts are priced equally and all bagels are priced equally and need to determine the total price of 5 donuts and 3 bagels. Let’s start by defining some variables. D = the price per donut B = the price per bagel Thus we need to determine: 5D + 3B = ? Statement One Alone: At the bakery, the total price of 10 donuts and 6 bagels is $12.90. Using the information in statement one, we can create the following equation: 10D + 6B = 12.90 We can simplify the equation by dividing the entire equation by 2. 5D + 3B = 6.45 Thus, the price for 5 donuts and 3 bagels is $6.45. Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E. Statement Two Alone: At the bakery, the price of a donut is $0.15 less than the price of a bagel. We can express D in terms of B: D = B  0.15 Substituting B – 0.15 for D, we get: 5(B – 0.15) + 3B 5B – 0.75 + 3B 8B – 0.75 However, without knowing anything about the price of either D or B, or the total amount spent, we cannot determine the sum of 5D + 3B. Thus, statement two is insufficient. The answer is A. While I do understand your explanation, I have a different viewpoint.
Its commonly known that if we have two unknowns , we need two equations to solve the Q.
In this Q, from(1) 10x +6y = 12.90 from (2) x = y  0.15
If I see this, the first thing which comes to my mind is option C, ( 2 unknowns x, y and we can solve this with two equations) How to negate this line of thought ?



Manager
Joined: 12 Jun 2016
Posts: 216
Location: India
Concentration: Technology, Leadership
WE: Sales (Telecommunications)

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
29 Jul 2017, 19:19
Hello mqdn, In DS each of the statement has to be checked for sufficiency in Isolation First.. Meaning, when we consider S1 the information in S2 should not be taken in consideration and Vice Versa. We need to Move to consider both statements together only if Each statement by itself is not sufficient. In this question, Since S1 alone is sufficient, we dont even need to check for S1+S2. The correct answer is A. PS: The AD/BCE technique by MGMAT or 12TEN method by Kaplan are both great ways to remember this. mqdn wrote: I found the answer using both of the statements.
1) 10d + 5b = 12.90 2) d = b  0.15 10(b0.15)+6b=12.90 10b1.5+6b=12.90 16b=14.4 b=0.9 [substitute for b in 2nd equation] d=0.90.15=0.75 5(0.75)+3(0.9)=6.45, which is equal to 12.90(0.5)
_________________
My Best is yet to come!



Manager
Joined: 12 Jun 2016
Posts: 216
Location: India
Concentration: Technology, Leadership
WE: Sales (Telecommunications)

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
29 Jul 2017, 19:27
Hello Manonamission, My 50 cents here. You are absolutely right  2 unknowns x, y and we can solve this with two equations. But if we look at the question, we dont need value of the two unknown. We need the sum of 5 donuts and 3 Bagels. This or something similar like this (Sum of unknowns) should set off an alarm for us. Maybe, Just MAYBE we dont need two equations to solve this. Probably thats one to avoid falling into the 'C" trap in this question. I hope this helps. Manonamission wrote: ScottTargetTestPrep wrote: Walkabout wrote: At a bakery, all donuts are priced equally and all bagels are priced equally. What is the total price of 5 donuts and 3 bagels at the bakery?
(1) At the bakery, the total price of 10 donuts and 6 bagels is $12.90. (2) At the bakery, the price of a donut is $0.15 less than the price of a bagel. We are given that all donuts are priced equally and all bagels are priced equally and need to determine the total price of 5 donuts and 3 bagels. Let’s start by defining some variables. D = the price per donut B = the price per bagel Thus we need to determine: 5D + 3B = ? Statement One Alone: At the bakery, the total price of 10 donuts and 6 bagels is $12.90. Using the information in statement one, we can create the following equation: 10D + 6B = 12.90 We can simplify the equation by dividing the entire equation by 2. 5D + 3B = 6.45 Thus, the price for 5 donuts and 3 bagels is $6.45. Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E. Statement Two Alone: At the bakery, the price of a donut is $0.15 less than the price of a bagel. We can express D in terms of B: D = B  0.15 Substituting B – 0.15 for D, we get: 5(B – 0.15) + 3B 5B – 0.75 + 3B 8B – 0.75 However, without knowing anything about the price of either D or B, or the total amount spent, we cannot determine the sum of 5D + 3B. Thus, statement two is insufficient. The answer is A. While I do understand your explanation, I have a different viewpoint.
Its commonly known that if we have two unknowns , we need two equations to solve the Q.
In this Q, from(1) 10x +6y = 12.90 from (2) x = y  0.15
If I see this, the first thing which comes to my mind is option C, ( 2 unknowns x, y and we can solve this with two equations) How to negate this line of thought ?
_________________
My Best is yet to come!



NonHuman User
Joined: 09 Sep 2013
Posts: 9091

Re: At a bakery, all donuts are priced equally and all bagels
[#permalink]
Show Tags
01 Aug 2018, 23:58
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: At a bakery, all donuts are priced equally and all bagels &nbs
[#permalink]
01 Aug 2018, 23:58






