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Monday, August 21 2017 @ 01:42 AM CDT
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 Nanyang Maths Paper 2011 Q 30 .
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By: verachen (offline)  Sunday, August 19 2012 @ 01:17 AM CDT (Read 1397 times)  
verachen

Hi , it's my Maths exam soon and I don't know how to do this question . Please help me asap by Mon . Please kindly explain it for me to understand , your help is appreciated ! This is the question .

Yusof took 30 minutes to clean his father's car while his elder brother only took 15 minutes to clean it. How long will both of them take to clean the car together?

Ans : 10 minutes .

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By: echeewh (offline)  Sunday, August 19 2012 @ 05:41 AM CDT  
echeewh

Hey Vera,

Following pls find my worked solution.


This is a Rate question, which means you have to calculate the proportion of car cleaned in 1 min first.

In 1 min,

Y: (1/30)
B: (1/15)

Y + B = (1/30) + (1/15) = (3/30) = (1/10)

<this means both cleaned (1/10) of the car in 1 min>

Y + B would take 10 minutes to clean the whole car together.

=====================

Trust this helps.

Do let me know again if there's any clarification.

Cheers,
Edward

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By: verachen (offline)  Monday, August 20 2012 @ 02:14 AM CDT  
verachen

Thanks alot ! But why must it be reduced to the simplest form? Can it be just 3/30? (:

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By: echeewh (offline)  Monday, August 20 2012 @ 10:34 PM CDT  
echeewh

Hi Vera,

Pls remember that all Fractions must be reduced to simple form!! The same with Ratio!

Cheers,
Edward

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