
By: drstevewu (offline) Thursday, May 03 2012 @ 11:32 PM CDT (Read 1021 times)



drstevewu 
If Adam gives Tom 6 sweets, the ratio of the number of sweets Adam will have to the number of sweets Tom will have is 2 : 5. If Tom gives Adam 8 sweets, the ratio of the number of sweets Adam will have to the number of sweets Tom will have is 1 : 2. How many sweets did Adam have at first?

Junior
Registered: 04/20/10 Posts: 27





By: echeewh (offline) Friday, May 04 2012 @ 12:30 AM CDT



echeewh 
Hi there,
Following pls find the worked solution:
Given that after A gave T 6 sweets, A : T = 2 : 5.
We now have the <Before> model as follows:
<Before>
A = 2p + 6
T = 5p  6
<Process>
T gave A 8 sweets.
Given that after the exchange, A : T = 1 : 2.
We now have the <After> model as shown:
<After>
A: 1u > 2p + 6 + 8 = 2p + 14
T: 2u > 5p  6  8 = 5p  14
Hence, we have ...
5p  14 = 2 x ( 2p + 14 )
5p  14 = 4p + 28
5p  4p > 28 + 14
1p > 42
A (at first) = 2p + 6 > ( 2 x 42 ) + 6
= 84 + 6 = 90
==================================
Trust the above helps.
Do not hesitate to clarify if necessary.
Cheers,
Edward

Active Member
Registered: 04/21/11 Posts: 623





By: drstevewu (offline) Friday, May 04 2012 @ 07:13 AM CDT



drstevewu 
Thanks so much Edward. Wow, it will be kinda difficult to explain such a sum to a P5.

Junior
Registered: 04/20/10 Posts: 27





By: echeewh (offline) Saturday, May 05 2012 @ 01:53 PM CDT



echeewh 
Well.. problem sums are becoming challenging these days. Reason why certain concepts n techniques are introduced to help solve most of these problem sums. There are over 10 of such skills n techniques that one can pick up by practising consistently and challenging oneself to variety of questions. Anyway with regards to the above solution, trust it can be explained using the model concept.
Cheers,
Edward

Active Member
Registered: 04/21/11 Posts: 623



