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Danny and Ian are munching on a jar full of candies. Had Dan

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Danny and Ian are munching on a jar full of candies. Had Dan [#permalink]

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19 Dec 2012, 23:40
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Danny and Ian are munching on a jar full of candies. Had Danny eaten alone it would have taken him 5 minutes to finish the candies in the jar. Had Ian eaten alone it would have taken him 10 minutes to finish half the jar. Since both of them are eating simultaneously, how long would it take them to empty the jar?

A. 2.5 minutes
B. 3 minutes
C. 3 minutes and 20 seconds
D. 6 minutes and 40 seconds
E. 4 minutes

Source: HULT
[Reveal] Spoiler: OA

Last edited by Bunuel on 20 Dec 2012, 02:32, edited 1 time in total.
Edited the question.
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Re: Danny and Ian are munching on a jar full of candies. [#permalink]

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19 Dec 2012, 23:42
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I thought it should be inverse of the combined rates which is (10*5)/(10+5)=50/15=3+ minutes right? OA says a different one.... what am I doing wrong?
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19 Dec 2012, 23:52
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Amateur wrote:
Danny and Ian are munching on a jar full of candies. Had Danny eaten alone it would have taken him 5 minutes to finish the candies in the jar. Had Ian eaten alone it would have taken him 10 minutes to finish half the jar.
Since both of them are eating simultaneously, how long would it take them to empty the jar?

2.5 minutes

3 minutes

3 minutes and 20 seconds

6 minutes and 40 seconds

4 minutes

Source: HULT

Hi,

Danny's does in 5 minutes
Ian finishes half in 10 minutes i.e finishes the jar in 20 minutes

Therefore Combined rate will be

1/5+1/20=1/T

5/20= 1/T ==> T = 4 min
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Re: Danny and Ian are munching on a jar full of candies. [#permalink]

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20 Dec 2012, 02:36
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Amateur wrote:
I thought it should be inverse of the combined rates which is (10*5)/(10+5)=50/15=3+ minutes right? OA says a different one.... what am I doing wrong?

We are told that Ian needs 10 minutes to finish HALF the jar, so he needs 20 minute to finish full jar.

Danny and Ian are munching on a jar full of candies. Had Danny eaten alone it would have taken him 5 minutes to finish the candies in the jar. Had Ian eaten alone it would have taken him 10 minutes to finish half the jar. Since both of them are eating simultaneously, how long would it take them to empty the jar?

A. 2.5 minutes
B. 3 minutes
C. 3 minutes and 20 seconds
D. 6 minutes and 40 seconds
E. 4 minutes

The rate of Danny is 1/5 jar/minute and the rate of Ian is 1/20 jar/minute, their combined rate is 1/5+1/20=1/4 jar/minute. Thus together they need 4 minutes to finish the jar.

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Re: Danny and Ian are munching on a jar full of candies. Had Dan [#permalink]

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29 Dec 2013, 19:37
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Re: Danny and Ian are munching on a jar full of candies. Had Dan [#permalink]

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28 Feb 2015, 13:09
Hello from the GMAT Club BumpBot!

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Re: Danny and Ian are munching on a jar full of candies. Had Dan [#permalink]

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28 Feb 2015, 14:15
Expert's post
Hi All,

This question is essentially a "Work Formula" question, since it has 2 people working on a task together. You have to be really careful with the details though, since the two given rates are NOT for the same task....

We're told that Danny can finish off the jar of candies in 5 minutes
We're told that Ian can finish off HALF the jar of candies in 10 minutes, which means that he can finish the WHOLE jar in 20 minutes.

We're asked how long it would take the two of them to finish the jar of candies together....

Work = (A)(B)/(A+B) where A and B are the individual rates of the two entities.

A = 5
B = 20

(5)(20)/(5+20) = 100/25 = 4 minutes to finish off the jar of candies.

[Reveal] Spoiler:
E

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Special Offer: Save $75 + GMAT Club Tests 60-point improvement guarantee www.empowergmat.com/ ***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*********************** Verbal Forum Moderator Joined: 29 Apr 2015 Posts: 901 Location: Switzerland Concentration: Economics, Finance WE: Asset Management (Investment Banking) Followers: 42 Kudos [?]: 925 [0], given: 302 Re: Danny and Ian are munching on a jar full of candies. Had Dan [#permalink] Show Tags 16 Jul 2015, 02:03 Bunuel wrote: Amateur wrote: I thought it should be inverse of the combined rates which is (10*5)/(10+5)=50/15=3+ minutes right? OA says a different one.... what am I doing wrong? We are told that Ian needs 10 minutes to finish HALF the jar, so he needs 20 minute to finish full jar. Danny and Ian are munching on a jar full of candies. Had Danny eaten alone it would have taken him 5 minutes to finish the candies in the jar. Had Ian eaten alone it would have taken him 10 minutes to finish half the jar. Since both of them are eating simultaneously, how long would it take them to empty the jar? A. 2.5 minutes B. 3 minutes C. 3 minutes and 20 seconds D. 6 minutes and 40 seconds E. 4 minutes The rate of Danny is 1/5 jar/minute and the rate of Ian is 1/20 jar/minute, their combined rate is 1/5+1/20=1/4 jar/minute. Thus together they need 4 minutes to finish the jar. Answer: E. OMG, actually this is a very simple question - the only problem here: if you go too fast and ignore the details, you will fail! (Finish HALF the jar...). With this trap this question becomes a 700+ question?! _________________ Saving was yesterday, heat up the gmatclub.forum's sentiment by spending KUDOS! PS Please send me PM if I do not respond to your question within 24 hours. Intern Joined: 11 Aug 2013 Posts: 23 Location: India Concentration: Finance, General Management GMAT 1: 620 Q47 V28 GPA: 3.23 WE: Information Technology (Investment Banking) Followers: 0 Kudos [?]: 10 [0], given: 17 Re: Danny and Ian are munching on a jar full of candies. Had Dan [#permalink] Show Tags 18 Jul 2015, 09:32 this is a straight forward rate question Rate of danny finishing the jar = 1/5 J/min Rate of Ian finishing the jar = 1/20 J/min. when both eating together = (1/5 +1/20) J/min =>1/4 J/min Hence they can together eat the whole jar in 4 mins _________________ Thanks Sindbad ---------------- Click +1 Kudos if my post helped... Verbal Forum Moderator Joined: 29 Apr 2015 Posts: 901 Location: Switzerland Concentration: Economics, Finance WE: Asset Management (Investment Banking) Followers: 42 Kudos [?]: 925 [0], given: 302 Re: Danny and Ian are munching on a jar full of candies. Had Dan [#permalink] Show Tags 23 Jul 2015, 21:38 Amateur wrote: Danny and Ian are munching on a jar full of candies. Had Danny eaten alone it would have taken him 5 minutes to finish the candies in the jar. Had Ian eaten alone it would have taken him 10 minutes to finish half the jar. Since both of them are eating simultaneously, how long would it take them to empty the jar? A. 2.5 minutes B. 3 minutes C. 3 minutes and 20 seconds D. 6 minutes and 40 seconds E. 4 minutes Source: HULT Plug in a good number for the number of candies. E.g. 10 and set up a rate work table: Danny: Rate 2 / Time 5 / Work 10 Ian: Rate 0.5 / Time 10 / Work 5 Combined Rate: 2.5 / Time 4 / Work 10 Answer E _________________ Saving was yesterday, heat up the gmatclub.forum's sentiment by spending KUDOS! PS Please send me PM if I do not respond to your question within 24 hours. Re: Danny and Ian are munching on a jar full of candies. Had Dan [#permalink] 23 Jul 2015, 21:38 Similar topics Replies Last post Similar Topics: 9 A jar full of whisky contains 40% alcohol. A part of this whisky is re 4 08 Mar 2016, 18:36 10 Amit and Ian paint a wall in alternating shifts. First Amit paints alo 5 17 Sep 2015, 00:51 4 Jar X is 16 full of water. Jar Y, which has half the capacity of Jar X 7 04 Feb 2015, 08:54 1 Ian is paid an hourly wage, totaling$400 for h hours of work in a wee 7 21 Jan 2015, 02:23
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