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A certain library assesses fines for overdue books as follow

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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 31 Dec 2015, 10:31
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HI dina98,

Many Test Takers become overly-obsessed with the implied 'level' of a question, when their focus should really be on whether the question was 'gettable' or not.

Ultimately, you should be measuring a question on a few key points:
1) Could you have gotten the question correct?
2) Was the work involved just too difficult (or was it actually really easy work)?
3) What could you do differently to make the overall process of dealing with the prompt easier (note-taking, organization, Tactics, etc.)?

The math involved in this prompt is remarkably low-level arithmetic, but the real 'test' here is how well you can organize the information involved and follow the instructions that the prompt gives you.

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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 15 Jun 2016, 20:16
Day 1 fine: 0.1
Day 2 fine: 0.1*2 = 0.2
Day 3 fine: 0.2*2 = 0.4 or 0.2+0.3 = 0.5
Since 0.4 < 0.5, fine = 0.4

Day 4 fine: 0.4*2 = 0.8 or 0.4 + 0.3 = 0.7
Since 0.7 < 0.8, fine = 0.7

Correct Option: B

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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 26 Apr 2017, 09:48
I still don't get this :(

day adding 0.30 doubling
1 0.10 0.10
2 0.40 0.20
3 0.70 0.40
4 1 0.80

Where am i going wrong?

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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 26 Apr 2017, 10:37
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Hi pra1785,

This question includes a 'conditional statement' that effects how you're supposed to handle each "step" in the math:

"for each additional day....., the total fine is EITHER increased by 30 cents OR doubled, whichever results in the LESSER AMOUNT."

Since we're asked to calculate a book that is 4 days overdue, we just have to consider each possible outcome on EACH day, then choose the one that leads to the "lesser amount"

Day 1: 10 cents

Day 2: 10 + 30 = 40 cents; 10(2) = 20 cents
20 cents is LOWER, so the fine is NOW 20 cents

Day 3: 20 + 30 = 50 cents; 20(2) = 40 cents
40 cents is LOWER, so the fine is NOW 40 cents

Day 4: 40 + 30 = 70 cents; 40(2) = 80 cents
70 cents is LOWER, so the final fine is 70 cents.

Final Answer:
[Reveal] Spoiler:
B


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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 03 Jul 2017, 03:54
This line in the question has killed me:
"the total fine is either increased by $0.30 or doubled."

What I have done:
Day 1: 0.1
Day 2: Double: 0.2
Day 3: Add 0.3
Day 4: Add 0.3
Then add all of them: 0.1+.2+.3+.3 = 0.9
The test writer has successfully tricked me to pick this incorrect option D by just one term in question prompt "Total Fine"
Please advise how to avoid such traps.

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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 03 Jul 2017, 18:40
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Hi zonebp,

The prompt states that the we are supposed to use the fine each day that ends in the "LESSER AMOUNT." Based on the work that you did, on Day 3 you did NOT choose the fine that ended in the lesser amount (doubling .2 to .4 would be less than adding .3 to .2).

Most little mistakes can be avoided by taking the proper notes on your pad.

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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 04 Dec 2017, 15:32
Wow, what a sneaky question. By the time I calculated 0.80, I had forgotten the little nuance (double OR add 0.30 whichever results in the lesser value). In my mind I was calculating the doubling condition and adding 0.30 condition separately! Sneaky, sneaky. In some cases when the answer seems too straightforward on the GMAT quant, something needs to be rechecked...

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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 11 Jan 2018, 13:41
sandranjeim wrote:
A certain library assesses fines for overdue books as follows. On the first day that a book is overdue, the total fine is $0.10. For each additional day that the book is overdue, the total fine is either increased by $0.30 or doubled, whichever results in the lesser amount. What is the total for a book on the fourth day it is overdue?

A. $0.60
B. $0.70
C. $0.80
D. $0.90
E. $1.00


On day 1, the fine is $0.10.
On day 2, we have two options:

1) 0.10 + 0.30 = $0.40
2) 0.10 x 2 = $0.20

Since option 2 is the lesser of the 2 fines, the total fine, as of day 2, is $0.20.

On day 3 we have two options:

1) 0.20 + 0.30 = $0.50
2) 0.20 x 2 = $0.40

Since option 2 is the lesser of the 2 fines, the total fine, as of day 3, is $0.40.

On day 4 we have two options:

1) 0.40 + 0.30 = $0.70
2) 0.40 x 2 = $0.80

Since option 1 is the lesser of the 2 fines, the total fine, as of day 4, is $0.70.

Answer: B
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Re: A certain library assesses fines for overdue books as follow [#permalink]

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New post 16 Jan 2018, 05:15
Bunuel wrote:
A certain library assesses fines for overdue books as follows. On the first day that a book is overdue, the total fine is $0.10. For each additional day that the book is overdue, the total fine is either increased by $0.30 or doubled, whichever results in the lesser amount. What is the total for a book on the fourth day it is overdue?

A. $0.60
B. $0.70
C. $0.80
D. $0.90
E. $1.00

Notice that, fines are already cumulative: "For each additional day that the book is overdue, the total fine is ..."

1st day fine - 0.1
2nd day fine - 0.1*2 = 0.2 (as doubling gives lower value)
3rd day fine - 0.2*2 = 0.4 (as doubling gives lower value)
4th day fine - 0.4 + 0.3 = 0.7 (as doubling gives higher value we add 0.3 this time)

Answer: B.


The question states that for each additional day the total fine is either increased by 0.3 or doubled. doesnt this state the reasoning as follows,

Day 1- 0.1
Day 2- min(0.1*2, 0.3)=0.2 => total till day 2 = 0.3
Day 3 - min(0.3*2, 0.3)=0.3 =>total till day 3 = 0.6
Day 4 - min(0.6*2, 0.3)=0.3 => total till day 4 = 0.9

Please explain why it is not so?

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A certain library assesses fines for overdue books as follow [#permalink]

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New post 16 Jan 2018, 05:21
JanarthCj wrote:
Bunuel wrote:
A certain library assesses fines for overdue books as follows. On the first day that a book is overdue, the total fine is $0.10. For each additional day that the book is overdue, the total fine is either increased by $0.30 or doubled, whichever results in the lesser amount. What is the total for a book on the fourth day it is overdue?

A. $0.60
B. $0.70
C. $0.80
D. $0.90
E. $1.00

Notice that, fines are already cumulative: "For each additional day that the book is overdue, the total fine is ..."

1st day fine - 0.1
2nd day fine - 0.1*2 = 0.2 (as doubling gives lower value)
3rd day fine - 0.2*2 = 0.4 (as doubling gives lower value)
4th day fine - 0.4 + 0.3 = 0.7 (as doubling gives higher value we add 0.3 this time)

Answer: B.


The question states that for each additional day the total fine is either increased by 0.3 or doubled. doesnt this state the reasoning as follows,

Day 1- 0.1
Day 2- min(0.1*2, 0.3)=0.2 => total till day 2 = 0.3
Day 3 - min(0.3*2, 0.3)=0.3 =>total till day 3 = 0.6
Day 4 - min(0.6*2, 0.3)=0.3 => total till day 4 = 0.9

Please explain why it is not so?


This is explained in the very first sentence of the solution (as well as in several other posts in this thread).
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A certain library assesses fines for overdue books as follow   [#permalink] 16 Jan 2018, 05:21

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