
By: achieve_goal (offline) Wednesday, May 30 2012 @ 02:40 AM CDT (Read 792 times)



achieve_goal 
1. Mandy had some money. After spending $31 on 5 notebooks & 8 files,she was short of $0.40 if she were to buy another notebook. However she would have $0.60 left if she were to buy one more file.
(a) How much did a notebook cost?
(b) How much money did Mandy have?
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2.There were 800 people at a party. 3/8 of them were were women and the rest were men. After 1 hour, some men left the party and the number of men became 2/5 of the number of the remaining people. Another 15 mins later, some women left the party and the number of men remaining at the party was 5/7 of the number of people who were still at the party. How many people were still at the party?
//Pls help me. Thank u.

Regular Member
Registered: 09/14/11 Posts: 102





By: echeewh (offline) Thursday, May 31 2012 @ 09:18 PM CDT



echeewh 
Hey there,
Following pls find the worked solutions:
Q1.
Note: ****  fillup/buffer whitespace for alignment purpose ( i.e. imagine *** as whitespace )
(a)
*****31.00 1N
<><>
<>
*************************0.40

<><><>
**31.00******1F 0.60
Applying Gap & Difference method, we have ...
1N  1F = 1.00  (1)
5N + 8F = 31.00  (2)
As question is interested in N, we shall eliminate F in the following manner:
(1)x8: 8N  8F = 8.00 (3)
Comparing (3) and (2),
(2) + (3):
5N + 8F + 8N  8F = 31.00 + 8.00
13N = 39
1N = 39 ÷ 13 = $3
(b)
Amt of money M had = 31 + 1N  0.40
= 31 + 3  0.40 = $33.60
==========================================================================
Q2.
<Before>
W: (3/8) x 800 = 300
M: 800  300 = 500
<Process1>
1 hr later, some M left party (i.e. W remains same)
<After>
W: 300
Given that remaining M is 2/5 of remaining total, that means the 300 W remaining makes up 3/5 of remaining total.
We now have ...
3/5 = 300
5/5 = 300 ÷ (3/5) = 300 x (5/3) = 500
M = 2/5 = (2/5) x 500 = 200
We now have a new <Before> and <After> ratio as follows:
<Before>
W : M
300 : 200
3 : 2  (1)
<Process2>
15 mins later, some W left party and remaining M makes up 5/7 of remaining total. So the <After> ratio becomes...
<After>
2 : 5  (2)
Applying <Unchanged Qty/Item> concept (since number of M remains unchanged), we take lowest common multiple of 2 and 5, which is 10.
(1)x5:
<Before>
W : M
15 : 10  (3)
(2)x2:
<After>
4 : 10  (4)
At this stage, total number of W and M is 500. Hence, we have ...
15u + 10u > 500
25u > 500
1u > 20
Number of people still remaining at party:
14u > 14 x 20 = 280
====================================================
Trust the above solution helps.. Do let me know again if it doesnt match the answerkey as these are not provided.
Cheers,
Edward

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





By: achieve_goal (offline) Sunday, June 03 2012 @ 03:42 AM CDT



achieve_goal 
Hi there, thanks 4 ur help!

Regular Member
Registered: 09/14/11 Posts: 102



