
By: Strawberry (offline) Tuesday, March 19 2013 @ 07:54 AM CDT (Read 1373 times)



Strawberry 
1. IN Primary 5K, 20 pupils are in the choir and 1/3 of the remaining pupils are in the school band. 1/4 of the class is in neither the choir nor the band. There is no pupils who joins both the choir and the school band. how many pupils are there in Primary 5K

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Registered: 01/31/09 Posts: 83





By: echeewh (offline) Tuesday, March 19 2013 @ 07:03 PM CDT



echeewh 
Hi Strawberry,
Following pls find my worked solution:
This is a partwhole model type question (Higher Order Remainder)
Given that (1/4)total is not in C nor B, we have the following model.
< Whole >

<20 >
***** <1u>< 2u >
1u = (1/3) of remaining class
2u > (1/4) total {since (1/4) of class is neither in Choir nor Band}
1u > (1/8) total
Since Remaining class makes up 3u,
Remaining class = 3u = (3/8)total
Hence, (5/8) total = 20
(8/8) total = 20 ÷ (5/8) = 20 × (8/5) = 32 pupils
============
Trust this helps.
Do let me know again if this is diferent from the Answerkey or if there's further clarification.
Cheers,
Edward

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Registered: 04/21/11 Posts: 623





By: Strawberry (offline) Saturday, March 23 2013 @ 10:23 PM CDT



Strawberry 
Thanks.... but how do we know that we have to make it to 1/8

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Registered: 01/31/09 Posts: 83





By: echeewh (offline) Sunday, March 24 2013 @ 05:35 PM CDT



echeewh 
Hi Strawberry,
Not quite sure what u mean by ... "but how do we know that we have to make it to 1/8"
Looking at my solution, the only portion where it has "1/8" is the (1/8) total. This is calculated for the 1u, where 2u > (1/4) total.
Does this answer your question???
Do let me know again if there's further clarification.
Rgds,
Edward

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



