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17 Dec 2013, 17:06
2
7
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Difficulty:

55% (hard)

Question Stats:

60% (01:01) correct 40% (01:15) wrong based on 621 sessions

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The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

(1) The cost of the phone call was less than $4.16 (2) The cost of the phone call was greater than$3.35

While this is a seemingly simple min/max problem, I was wondering if there is a faster way to deal with decimals—as it took me ~4mins to arrive at the solution.

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Re: The cost of a certain phone call was $0.75 for the first 3 [#permalink] ### Show Tags 18 Dec 2013, 01:34 5 3 megafan wrote: The cost of a certain phone call was$0.75 for the first 3 minutes and $0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes (1) The cost of the phone call was less than$4.16
(2) The cost of the phone call was greater than $3.35 While this is a seemingly simple min/max problem, I was wondering if there is a faster way to deal with decimals—as it took me ~4mins to arrive at the solution. The cost of a certain phone call was$0.75 for the first 3 minutes and $0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes According to the above the cost for n minutes, where n>3, is $$75 + (n-3)*20=20n+15$$ cents. W need to find whether n>15. The cost for 15 minutes is $$20n+15=20*15+15=315$$ cents, so we need to find whether the cost is greater than 315 cents. (1) The cost of the phone call was less than$4.16. Not sufficient.

(2) The cost of the phone call was greater than $3.35. Sufficient. Answer: B. _________________ Math Expert Joined: 02 Sep 2009 Posts: 46128 Re: The cost of a certain phone call was$0.75 for the first 3 [#permalink]

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18 Dec 2013, 01:39
2
10
Bunuel wrote:
megafan wrote:
The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

(1) The cost of the phone call was less than $4.16 (2) The cost of the phone call was greater than$3.35

While this is a seemingly simple min/max problem, I was wondering if there is a faster way to deal with decimals—as it took me ~4mins to arrive at the solution.

The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

According to the above the cost for n minutes, where n>3, is $$75 + (n-3)*20=20n+15$$ cents. W need to find whether n>15. The cost for 15 minutes is $$20n+15=20*15+15=315$$ cents, so we need to find whether the cost is greater than 315 cents.

(1) The cost of the phone call was less than $4.16. Not sufficient. (2) The cost of the phone call was greater than$3.35. Sufficient.

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Re: The cost of a certain phone call was $0.75 for the first 3 [#permalink] ### Show Tags 02 Jul 2014, 08:05 Hi Bunuel, I tried solving this question by following method and i feel both the statements are not sufficient to get an answer. given: The cost of a certain phone call was$0.75 for the first 3 minutes and $0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes let's assume phone call lasted for x mins 1) The cost of the phone call was less than$4.16
75+x*20< 416
x<17.04.. Not sufficient as x can be > , < or = 15

2) The cost of the phone call was greater than $3.35 75+x*20>335 x>13 again not sufficient combining both 13<x<17..not sufficient.. Please let me know where i am going wrong. Manager Joined: 28 Apr 2014 Posts: 249 Re: The cost of a certain phone call was$0.75 for the first 3 [#permalink]

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02 Jul 2014, 21:26
varikaur wrote:
Hi Bunuel,
I tried solving this question by following method and i feel both the statements are not sufficient to get an answer.

given: The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

let's assume phone call lasted for x mins
1) The cost of the phone call was less than $4.16 75+x*20< 416 x<17.04.. Not sufficient as x can be > , < or = 15 2) The cost of the phone call was greater than$3.35
75+x*20>335
x>13 again not sufficient

combining both 13<x<17..not sufficient..
Please let me know where i am going wrong.

I get the fallacy mate. The call of 0.20 is after three minutes. So once you as per you calculation get 13 , you have to add the first 3 minutes. Thus you get the total time as 13 + 3 = 16 minutes
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Re: The cost of a certain phone call was $0.75 for the first 3 [#permalink] ### Show Tags 02 Dec 2014, 21:00 1 Lets t = 15 then C = .75 + 12*.20 = 3.15. basically is C >$3.15

1. C < 4.16 not sufficient
2. C > 3.35 so C is definitely greater then 3.15 Sufficient.

megafan wrote:
The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

(1) The cost of the phone call was less than $4.16 (2) The cost of the phone call was greater than$3.35

While this is a seemingly simple min/max problem, I was wondering if there is a faster way to deal with decimals—as it took me ~4mins to arrive at the solution.

_________________

Manager
Joined: 28 Sep 2013
Posts: 87
GMAT 1: 740 Q51 V39
Re: The cost of a certain phone call was $0.75 for the first 3 [#permalink] ### Show Tags 09 Aug 2016, 18:39 Bunuel wrote: megafan wrote: The cost of a certain phone call was$0.75 for the first 3 minutes and $0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes (1) The cost of the phone call was less than$4.16
(2) The cost of the phone call was greater than $3.35 While this is a seemingly simple min/max problem, I was wondering if there is a faster way to deal with decimals—as it took me ~4mins to arrive at the solution. The cost of a certain phone call was$0.75 for the first 3 minutes and $0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes According to the above the cost for n minutes, where n>3, is $$75 + (n-3)*20=20n+15$$ cents. W need to find whether n>15. The cost for 15 minutes is $$20n+15=20*15+15=315$$ cents, so we need to find whether the cost is greater than 315 cents. (1) The cost of the phone call was less than$4.16. Not sufficient.

(2) The cost of the phone call was greater than $3.35. Sufficient. Answer: B. What is the flaw in my reasoning - 0.75X3 + A X 0.2 = Total Cost. Where A is the # of Minutes after 3 Minutes. Basically, now we boil down to if A>12 Statement 1 = 0.75X3 + A X 0.2 = 4.16 A = 9.55 Minutes - That means A is not greater than 12. Hence with the calculation we did above we can clearly say that this statement is sufficient to forecast that A is not greater than 12. _________________ Richa Champion | My GMAT Journey - 470 720 740 Target 760+ Not Improving after Multiple attempts. I can guide You. Contact me richacrunch2@gmail.com Math Expert Joined: 02 Sep 2009 Posts: 46128 Re: The cost of a certain phone call was$0.75 for the first 3 [#permalink]

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10 Aug 2016, 01:06
RichaChampion wrote:
Bunuel wrote:
megafan wrote:
The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

(1) The cost of the phone call was less than $4.16 (2) The cost of the phone call was greater than$3.35

While this is a seemingly simple min/max problem, I was wondering if there is a faster way to deal with decimals—as it took me ~4mins to arrive at the solution.

The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

According to the above the cost for n minutes, where n>3, is $$75 + (n-3)*20=20n+15$$ cents. W need to find whether n>15. The cost for 15 minutes is $$20n+15=20*15+15=315$$ cents, so we need to find whether the cost is greater than 315 cents.

(1) The cost of the phone call was less than $4.16. Not sufficient. (2) The cost of the phone call was greater than$3.35. Sufficient.

What is the flaw in my reasoning -

0.75X3 + A X 0.2 = Total Cost.

Where A is the # of Minutes after 3 Minutes.

Basically, now we boil down to if A>12

Statement 1 =
0.75X3 + A X 0.2 = 4.16
A = 9.55 Minutes - That means A is not greater than 12. Hence with the calculation we did above we can clearly say that this statement is sufficient to forecast that A is not greater than 12.

You should read the stem and the solution more carefully.

1. The cost of a certain phone call was $0.75 for the first 3 minutes, not$0.75 for each of the first 3 minutes;
2. A in your solution must be more than 15, not more than 12;
3. (1) says that the cost of the phone call was less than $4.16, not equal to$4.16.

So, it should be 0.75+ A *0.2 < 4.16 --> A < 17.05.
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02 Dec 2017, 10:55
megafan wrote:
The cost of a certain phone call was $0.75 for the first 3 minutes and$0.20 for each additional minute after the first 3 minutes. Did the phone call last longer than 15 minutes

(1) The cost of the phone call was less than $4.16 (2) The cost of the phone call was greater than$3.35

For First 3 mins, the cost = 0.75$For each additional minute after the first 3 minutes, the cost = 0.20$

SO, calculate the cost for the 15 minutes -- cost for first 3 mins + cost for each additional minute after the first 3 minutes
= 0.75$+ 12*0.20$ = 0.75$+ 2.40$ = 3.15$Now, Question becomes whether the cost of phone call > 3.15$?

1. <4.16$so the cost can OR cannot be > 3.15$ Insufficient

2. >3.35$Sufficient. As cost > 3.35$ will always be > than 3.15$. Answer : B Re: The cost of a certain phone call was$0.75 for the first 3   [#permalink] 02 Dec 2017, 10:55
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