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# If the length of Wanda's telephone call was rounded up to

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Math Expert
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If the length of Wanda's telephone call was rounded up to [#permalink]

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14 Jun 2012, 03:09
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Difficulty:

25% (medium)

Question Stats:

70% (02:14) correct 30% (00:54) wrong based on 907 sessions

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If the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call?

(1) The total charge for Wanda's telephone call was $6.50. (2) Wanda was charged$0.50 more for the first minute of the telephone call than for each minute after the first.

Diagnostic Test
Question: 27
Page: 25
Difficulty: 650
[Reveal] Spoiler: OA

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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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14 Jun 2012, 03:10
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SOLUTION

If the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call?

(1) The total charge for Wanda's telephone call was $6.50. Clearly insufficient since we don't know the cost per minute of call. (2) Wanda was charged$0.50 more for the first minute of the telephone call than for each minute after the first. So, if the first minute costs $$(x+0.5)$$ then each succeeding minute costs $$x$$. Still not sufficient.

(1)+(2) We have that $$(x+0.5)+x(n-1)=6.5$$ --> $$xn=6$$, where $$n$$ is the number of minutes. We have one equation and two unknowns, hence we cannot solve for $$n$$. Not sufficient.

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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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14 Jun 2012, 05:27
Hi,

Difficulty level: 600

To find the time duration of Wanda's call,

Using (1),
Total charge for the call = $6.5, we neither know the number of minutes nor call charges. Insufficient. Using (2), Wanda was charged$0.50 more for the first minute of the telephone call than for each minute after the first.
x+0.5 for first minute,
for second minute x, & so on,
for the whole call total charges would be nx+0.5 (n = number of minutes)
or nx+0.5 = 6.5
or nx = 6 (1*6 or 6*1 or 2*3 or 3*2)
thus, (n,x) = (1,6) or (6,1) or ....
which means, for 1 min $6 can be charged. or for 6 mins$1 can be charged. Insufficient.

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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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15 Jun 2012, 13:03
clearly ans is E.

well explained above.

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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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16 Jun 2012, 04:40
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We have to find the duration of the call say N minutes.

1. Statement 1: It gives information about the cost of total call however we do not know per minute cost hence can not calculate the minutes.

2. Statement 2: We know that the cost of first minute was higher by 0.50 cents however we do not know the cost of subsequent minutes. Secondly, we cant calculate the duration of the call with this information.

Put together, we know the total cost and also know that cost of first minute was higher by 0.50. If for example cost of subsequent minutes were 50 cents, the total duration would have been 12 minutes. Reduce the cost of call made after first minute, the duration will change.

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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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17 Jun 2012, 08:28
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IMO also E is the correct answer. Agree with Manjeet's sol
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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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17 Jun 2012, 08:49

The question probably might be D if it had asked the maximum or minimum number of calls she made.
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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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22 Jun 2012, 03:56
SOLUTION

If the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call?

(1) The total charge for Wanda's telephone call was $6.50. Clearly insufficient since we don't know the cost per minute of call. (2) Wanda was charged$0.50 more for the first minute of the telephone call than for each minute after the first. So, if the first minute costs $$(x+0.5)$$ then each succeeding minute costs $$x$$. Still not sufficient.

(1)+(2) We have that $$(x+0.5)+x(n-1)=6.5$$ --> $$xn=6$$, where $$n$$ is the number of minutes. We have one equation and two unknowns, hence we cannot solve for $$n$$. Not sufficient.

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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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23 Jul 2012, 07:29
Total call minutes=Total call cost/Cost per min
(i) m=6.5/c insufficient
(ii)m={(c+0.5)+c*(m-1)}/c insufficient
combining;
m can't be calculated
so, (E)
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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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20 Aug 2013, 03:50
Bumping for review and further discussion.
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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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20 Aug 2013, 03:51
The Official Guide Quantitative Question Directory: the-official-guide-quantitative-question-directory-143450.html (All OG13 questions with solutions)
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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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18 Jul 2015, 20:22
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).

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Re: If the length of Wanda's telephone call was rounded up to [#permalink]

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24 Dec 2016, 04:02
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).

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If the length of Wanda's telephone call was rounded up to [#permalink]

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29 Apr 2017, 02:26
Bunuel wrote:
SOLUTION

If the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call?

(1) The total charge for Wanda's telephone call was $6.50. Clearly insufficient since we don't know the cost per minute of call. (2) Wanda was charged$0.50 more for the first minute of the telephone call than for each minute after the first. So, if the first minute costs $$(x+0.5)$$ then each succeeding minute costs $$x$$. Still not sufficient.

(1)+(2) We have that $$(x+0.5)+x(n-1)=6.5$$ --> $$xn=6$$, where $$n$$ is the number of minutes. We have one equation and two unknowns, hence we cannot solve for $$n$$. Not sufficient.

I've just an important question (at least imo). I solved the problem correctly but it took me a too much time. I also ended up with an equation with two unknowns. But since they said "telephone call was rounded up to the nearest whole minute" i was a bit suspicious and tried out numbers in order to make sure that there is more than one solution. Often in DF we make the argument that we can't solve an equation with two unknown, but in fact sometimes we can infer that theres only one plausible solutions (For Instance in the following problem)

A certain fruit stand sold apples for $0.70 each and bananas for$0.50 each. If a customer purchased both apples and bananas from the stand for a total of $6.30, what total number of apples and bananas did the customer purchase ? So my question is just, when we can make the argument that we are dealing with an equation with two unknowns and when we can't make this argument. hope its clear Thank you ! If the length of Wanda's telephone call was rounded up to [#permalink] 29 Apr 2017, 02:26 Similar topics Replies Last post Similar Topics: 3 If Carla, Nora, and Wanda have a total of$48, how much money does Car 1 26 May 2017, 11:28
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