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Sunday, December 17 2017 @ 03:40 AM CST
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 Can't make sense of this question.
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By: drstevewu (offline)  Friday, July 26 2013 @ 10:58 AM CDT (Read 1227 times)  
drstevewu

Hi, I can't make sense of the following question. Need your help.

Question: Harry, Larry and Sean were to share a box of marbles. Harry took 1/5 more than his rightful share of marbles. Larry took 1/3 of the remaining marbles. Sean took his rightful share of marbles. After that, there were 40 marbles left. How many marbles were there in the box at first?


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By: echeewh (offline)  Friday, July 26 2013 @ 05:17 PM CDT  
echeewh

Hi <drstevewu>,

My thoughts are that the question may not have been clear enough. I think perhaps one can take it that the box of marbles was shared equally among the 3 boys. Then I believe you can work out the answer easily. And btw, is there any marks given for this question? Or is there an <Answerkey>?. Thank you.

Hope you find this helpful.

Cheers,
Edward

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By: drstevewu (offline)  Saturday, July 27 2013 @ 04:06 AM CDT  
drstevewu

Hi Edward,

Thanks for your reply. I have the answer key but honestly I don't quite agree with it. The answer key is as follow:

"Let there be 30 units of marbles at first, and each boy was to take 10 units.
Harry took 10 + 2 = 12 units, and there were 30 - 12 = 18 units left.
Larry took 1/3 x 18 units = 6 units, and there were 18 - 6 = 12 units left.
Sean took his rightful share of 10 units, and there were 12 - 10 = 2 units left.
2 units = 40 marbles
1 unit = 40/2 = 20 marbles.
At first, there were 30 units, = 30 x 20 = 600 marbles"

I don't agree in that part where it assume there were 30 units at first. I mean how can a student be able to assume there were "30 units" in the first place?

Thank you again for your help.

Cheers,
Steve Wu



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By: echeewh (offline)  Saturday, July 27 2013 @ 07:19 PM CDT  
echeewh

Hi Steve,

Yes you have my vote on that too ( with regards to the assumption used / stated in the Answerkey ). Big Grin

But I believe you do have a more appropriate solution for your child that gives the same result as 600.

Cheers and best regards,
Edward

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