
By: Strawberry (offline) Tuesday, March 19 2013 @ 08:00 AM CDT (Read 824 times)



Strawberry 
V, N and J had 258 Pokemon cards altogether at first. Later, V lost 10 cards, N's cards were doubled and J gave away 1/4 of his cards. In the end, V had half as many cards as N, and the the total number of cards V and N had was twice as many as what J had. What was the difference in the number of cards between J and V at first.

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Registered: 01/31/09 Posts: 83





By: echeewh (offline) Tuesday, March 19 2013 @ 08:42 PM CDT



echeewh 
hi Strawberry,
Following pls find my worked solution:
This is a <work backwards> type question using models.
<after>
V 
N 
Given that the total number of cards V and N had was twice as many as what J had, we split the V, N model above where 1 part(p) = 2 units(u) as follows.
V 
N 
J  *** { If V + N = 6u, then J = 3u }
Apply <work backwards> next to derive the <before> models.
<process>
J:  (1/4)
N: x 2
V:  10
Reverse these 3 processes and we have the following :
<before>
V <10>
N 
J 
Total: 258
8u > 258  10 = 248
1u > 31
J  V (at first) = 4u  2u  10 = 2u  10
2u  10 > (2 × 31)  10 = 62  10 = 52
===========
Trust this helps
Do let me know again if this is different from your Answerkey or if there's further clarification.
Cheers,
Edward

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Registered: 04/21/11 Posts: 627



