
By: karseng (offline) Sunday, March 18 2012 @ 05:30 AM CDT (Read 1458 times)



karseng 
Albert & Benny had $282. Benny had $4 more than Albert. Benny spent 1/2 as much as Albert and was left with twice as much as Albert. How much did Benny spend?

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Registered: 04/20/11 Posts: 3





By: RachelAng (offline) Tuesday, March 27 2012 @ 02:02 AM CDT



RachelAng 
282  4 = 278
278 / 2 = 139
A has 139
B has 139 + 4 = 143.
A spends S, then B spends S/2 or A spends 2S, B spends S.
A: 1 unit left + 2S = 139
B: 2 units left + S = 143
So 3S = 139 + 139  143
S = 45
B spent $45

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Registered: 01/23/11 Posts: 4





By: echeewh (offline) Tuesday, March 27 2012 @ 07:07 PM CDT



echeewh 
Alternative solution:
<before>
A= ( 282  4 ) / 2 = 139
B= 139 + 4 = 143
<spent>
A : B
2 : 1
<after>
A : B
1 : 2
139  2u > 1p  (1)
143  1u > 2p  (2)
Applying Simultaneous Concept / Compare & Replace method:
Since question is only interested in finding how much did Benny spend ( 1u ), we have:
(1) x 2: 278  4u > 2p  (3)
(3)  (2): 3u > 135
1u > 135 / 3
= $45
==========================
Hope this helps.
Cheers

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Registered: 04/21/11 Posts: 627



