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A bakery opened yesterday with its daily supply of 40 dozen

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A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 13 Aug 2012, 06:04
2
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A
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D
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  5% (low)

Question Stats:

96% (00:39) correct 4% (00:41) wrong based on 1745 sessions

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A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon, and 80 percent of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

Practice Questions
Question: 19
Page: 154
Difficulty: 550

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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 13 Aug 2012, 06:04
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SOLUTION

A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon, and 80 percent of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

20 rolls were sold sold by noon and 80% of the remaining 20 rolls were sold between noon and closing time, thus only 20% of these remaining 20 rolls had not been sold when the bakery closed. Hence 0.2*20=4 rolls had not been sold when the bakery closed.

Answer: D.
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Collection of Questions:
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 13 Aug 2012, 07:18
answer is D ...4 dozens ....

half sold by noon --> 20 dozens (20 *12 =240)
remaining --> 20 dozens i.e 240 eggs...
80% sold --> 80*240/100 =192 eggs
remaining 20 % --> 48 eggs (4 dozens ) --> answer
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 13 Aug 2012, 08:21
I'm also getting D, but the OA is E. Looking forward to the explanation.
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 13 Aug 2012, 08:26
Answer has to be 4 dozens, May be the OA is wrong :)
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 13 Aug 2012, 09:00
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 17 Aug 2012, 00:07
SOLUTION

A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon, and 80 percent of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

20 rolls were sold sold by noon and 80% of the remaining 20 rolls were sold between noon and closing time, thus only 20% of these remaining 20 rolls had not been sold when the bakery closed. Hence 0.2*20=4 rolls had not been sold when the bakery closed.

Answer: D.
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Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 02 Aug 2013, 11:56
worst question ever i thought the bakery would make rolls during the day. what kind of bakery doesn't bake their own rolls?
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 23 Jan 2014, 11:03
isn't 40 dozen rolls mean 40x12? If i go this bakery and say give me half a dozen rolls, they will charge me for 6 rolls. not 0.5 rolls. So the total rolls should be 40X12. half rolls sold by noon mean remaining is 20x12. 80% by closing means, 0.2x20x12 remaining = 48.

whats the trick here to choose value as 40 as a starting value for total rolls.

BTW, i choose D by ignoring "dozen" in the problem by just looking at the answer choices.
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 23 Jan 2014, 20:16
pradeepss wrote:
isn't 40 dozen rolls mean 40x12? If i go this bakery and say give me half a dozen rolls, they will charge me for 6 rolls. not 0.5 rolls. So the total rolls should be 40X12. half rolls sold by noon mean remaining is 20x12. 80% by closing means, 0.2x20x12 remaining = 48.

whats the trick here to choose value as 40 as a starting value for total rolls.

BTW, i choose D by ignoring "dozen" in the problem by just looking at the answer choices.


Read the question again: "How many dozen rolls had not been sold when the bakery closed yesterday?"

They want the answer in dozen rolls. You get the answer as 4 dozen rolls.
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 23 Jan 2014, 21:50
Bunuel wrote:
A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon, and 80 percent of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

Practice Questions
Question: 19
Page: 154
Difficulty: 550


40/2 * 20/100 = 4

Option D
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 09 Sep 2014, 22:53
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Bunuel wrote:
A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon, and 80 percent of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

Practice Questions
Question: 19
Page: 154
Difficulty: 550



half of the 40 dozen roll = 20

80% of 20 = 20*0.8 = 16

20-16 =4 , which is not sold.
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 15 Nov 2014, 02:17
40*12 to start with
20*12 sold by noon
(20/5*4)* 12= 16*12 sold by closing time (4/5 is 80%)
(20+16)*12= 36*12 sold
4*12 left = 4 dozen
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 11 Jan 2015, 08:27
Yes the "trick" is that they ask for dozen rolls. It is logical to calculaye the 40 dozens in the begining. And since it goes on exlpaining how many of the "rolls" were sold during the day, you sort of forget that it asks about dozens again in the end.

But still, if you do 48/12= 4, you end up with the correct answer.
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 21 Dec 2015, 08:08
easy question.

50% --> 20,
80% of 20 = 16.

40-20-16 =4 =answer
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 24 May 2016, 09:44
Bunuel wrote:
A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon, and 80 percent of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5


The bakery began the day with 40 dozen rolls. Half of the rolls were sold by noon, so we know by noon we had 40 x ½ = 20 dozen rolls sold. It follows that there were 20 dozen rolls remaining between noon and closing time.

We are next given that 80% of the remaining rolls were sold between noon and closing time. Since 80% were sold, 20% were left. This means:

rolls left when the bakery closed = 0.2 x 20 = 4 dozen rolls

Answer: D
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 05 Jul 2016, 03:13
Bunuel wrote:
A bakery opened yesterday with its daily supply of 40 dozen rolls. Half of the rolls were sold by noon, and 80 percent of the remaining rolls were sold between noon and closing time. How many dozen rolls had not been sold when the bakery closed yesterday?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

Practice Questions
Question: 19
Page: 154
Difficulty: 550


40*50%=20
20*80%=16

20-16=4
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Re: A bakery opened yesterday with its daily supply of 40 dozen  [#permalink]

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New post 31 Oct 2018, 23:31
A half dozen was sold by noon = 40/2 = 20
The remaining half dozen = 20
Now, 80% of the remaining half dozen is also sold = 80%*20 = 16dozen
How many were not sold?

We had total = 20 = 100%
80% were sold = -80%
Remaining = 20%

100% of 20 = 20
10% of 20 = 2
20% of 20 = 4 i.e. 2+2

The answer choice is D.
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Re: A bakery opened yesterday with its daily supply of 40 dozen &nbs [#permalink] 31 Oct 2018, 23:31
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