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Saturday, September 23 2017 @ 11:13 AM CDT
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 Help!! P6 Maths Question
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By: kkmg (offline)  Friday, September 20 2013 @ 10:39 AM CDT (Read 1386 times)  
kkmg

Please advice on the following question.

Joey alone takes 24 hr to knit a muffler. Tammy alone takes 32 hr to knit the same muffler. If Joey starts knitting first and leaves the remainder to Tammy, both of them will take 26 hr altogether to finish knitting the muffler. How many hours does Joey spend on knitting?

Thanks

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By: echeewh (offline)  Friday, September 20 2013 @ 08:08 PM CDT  
echeewh

Hey <kkmg>,

//updated 26/9/13 21 00
replaced "days" with "hours"
//


Following is my worked solution:

Let 1u be the number of hours J works on the muffler.

J completes
= (1/24)u (out of 1 whole muffler)

Given T completes remaining muffler in the remaining hours (time), we have ...

T completed
= (1/32) × (26 - u)
= (26/32) - (1/32)u (out of 1 whole muffler)

Adding both the above,

(1/24)u + (26/32) - (1/32)u = 1 (whole muffler)
(1/24)u - (1/32)u = 1 - (26/32)

LCM of 24, 32 is 96

(4/96)u - (3/96)u = (6/32)
(1/96)u = (6/32)
1u = (6/32) × 96 = 18

Hence, J spends 18 hours knitting.

========

Trust this helps.

Do let me know again if this is different from your <Answerkey> or if there's further clarification.

Cheers,
Edward

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By: kkmg (offline)  Friday, September 20 2013 @ 10:13 PM CDT  
kkmg

Thanks Edward for your solution. Really appreciate.

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By: echeewh (offline)  Thursday, September 26 2013 @ 08:05 AM CDT  
echeewh

Hey <kkmg>

Apologise for my mistake here. Instead of "days", it should have been "hours". Hence my worked solution above was re-edited as such, on 26/9/13, 21 00.

Any inconvenience caused is regretted.

Best regards,
Edward

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