
By: geniuskids (offline) Friday, September 20 2013 @ 03:20 AM CDT (Read 993 times)



geniuskids 
Hi there! Pls help me with this question.
Thanks

Active Member
Registered: 11/12/11 Posts: 169





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 (: )

Junior
Registered: 05/07/10 Posts: 15





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

Active Member
Registered: 04/21/11 Posts: 627





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!

Active Member
Registered: 11/12/11 Posts: 169



