
By: JessicaTan (offline) Monday, February 25 2013 @ 02:28 AM CST (Read 605 times)



JessicaTan 
Please help with the below working solution.
1) Candy had 500 stamps in her collection of which 30% were from Singapore. How many Singapore stamps must her brother give her to increase the number of Singapore stamps in her collection to 44%.
2) Mark & Geroge shared a sum of money. Mark received $379. If Mark received $60 more, the amount of money Geroge received would be reduced by 15%. Find the amount of money shared by the boys.
thanks

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Registered: 10/17/09 Posts: 82





By: echeewh (offline) Monday, February 25 2013 @ 04:04 AM CST



echeewh 
hey Jessica,
Following pls find my worked solutions:
Q1
<before>
S : N
3 : 7
<after>
S : N
44 : 56
11 : 14
Given that number of NonSingapore stamps (N) remains the same / unchanged, we apply <Unchanged Qty> concept.
Multiply <before> ratio 2x, giving ...
<before1>
S : N
6 : 14
and, we have units of N stamps remain unchanged.
Given that there were 500 stamps at first, we have ...
20u > 500
1u > 25
Comparing <before1> and <after> ratio, there's an increase of 5u of S stamps.
Hence, 5u > 5 × 25 = 125
=============
Q2
Given that the sum of money is fixed, if M received $60 more, then G received $60 less.
Given that the amount of money G received would be reduced by 15%, we have ...
15% = 60
G: 100% = (60 ÷ 15) × 100 = 400
Amount of money shared = 400 + 379 = $779
===================
Trust the above helps.
Do let me know again if the answers are different from your Answerkey or if there's further clarification.
Cheers,
Edward

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





By: JessicaTan (offline) Tuesday, February 26 2013 @ 03:40 AM CST



JessicaTan 
Thanks a lot, Edward
Rdgs
Jessica

Regular Member
Registered: 10/17/09 Posts: 82



