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Sunday, November 19 2017 @ 11:42 AM CST
 Forum Index >  Test Paper Related >  Primary 6 Matters
 2013 Prelims! P6 Maths! Red Swastika Paper 2 Q17
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By: geniuskids (offline)  Friday, September 20 2013 @ 03:20 AM CDT (Read 993 times)  
geniuskids

Hi there! Pls help me with this question.

Thanks

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By: verachen (offline)  Friday, September 20 2013 @ 08:35 AM CDT  
verachen

Dear geniuskids,

Note that the number of days took are different for the two scenarios .

1st scenario : If C ate 6 chocolates and D ate 3 chocolates each day, C would still have 3 chocolates when D had eaten up all his chocolates
2nd scenario : If C ate 3 chocolates while D ate 6 each day, C would still have 30 chocolates left when D had eaten all of his

For 1st scenario, let ' z ' be the number of days took
For 2nd scenario, let ' y ' be the number of days took

So,
C : D C : D
6z : 3z 3y : 6y
+3 +30

6z + 3 = 3y + 30
3z = 6y
1z = 2y
6z = 12y
12y + 3 = 3y + 30
12y - 3y = 9y
30 - 3 = 27
9y --> 27
1y --> 27 / 9 = 3
y --> 3
3y --> 3 x 3 = 9
9 + 30 = 39 ----- ( C )
6y --> 3 x 6 = 18 ----- ( D )

Ans :
a ) 39
b ) 18

Yours sincerely,
Vera (:
( If you are a P6, good luck for your PSLE . I'm a P6 student as well (: )

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By: echeewh (offline)  Friday, September 20 2013 @ 06:26 PM CDT  
echeewh

Hi <geniuskids> ,

Following is a variation using Model method (with Ratio) as follows:

<1st IF>

C : D
6 : 3
2 : 1

C |-----|-----|<-3->|
D |-----|

<2nd IF>

C : D
3 : 6
1 : 2

****<----- 30 ----->
C |--|--|--|--|<-3->|
D |--|--|

Referring to the <2nd IF> model and using <Gap & Difference> method, we have ...

3u --> 27
1u --> 9

(a)
C = 1u + 30 --> 9 + 30 = 39

(b)
D = 2u --> 2 × 9 = 18

========

Trust this helps too..

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

Vera,
Referring to your earlier post on your Speed and 'Chickens & Ducks" problem, we noted something's not quite right with the latter. Wonder if you have managed to review the question and advise if there's any changes to it. Thank you and all the best in your PSLE too.


Cheers and all the very best in your PSLE,
Edward

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By: geniuskids (offline)  Saturday, September 21 2013 @ 08:20 AM CDT  
geniuskids

Hi verachen, thank you and all the best to your PSLE too.

Hi Edward, thank you. I do understand yr method better! Big Grin

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