
By: Strawberry (offline) Sunday, May 06 2012 @ 07:06 AM CDT (Read 1306 times)



Strawberry 
1. Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil, find the cost of a pencil.
2. Ms Lee baked 24 more chocolate muffins than banana muffins. After she gave away1/6 of the chocolate muffins and 3/8 of the banana muffins, she left with 35 more chocolate muffins than banana muffins. How many chocolate muffins did she bake at first?

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Registered: 01/31/09 Posts: 83





By: echeewh (offline) Sunday, May 06 2012 @ 10:18 PM CDT



echeewh 
Hey strawberry,
Following pls find worked solution:
Q1.
Use Comparison model to calculate cost of notebooks (N) and pencils (P) as follows:
21.60  2.40 = 19.20
19.20 / 2 = 9.60 ( Cost of P )
Cost of N = 9.60 + 2.40 = 12.00
Given that 4u of P and 1u of N were bought, we can now calculate the cost of 1u of P.
1u of P = 9.60 / 4 = 2.40
1u of N = 12.00
Difference in cost ( 1u N  1u P )
= 12.00  2.40 = 9.60
Given that N  P = 3.20,
1u N = 9.60 / 3.20 = 3 ( 1u N = 1u P )
Number of P = 4u = 4 x 3 = 12
Cost of 1P = 9.60 / 12 = $0.80 ( 80 cents )
=======================================
Q2
Using Simultaneous Eqn method ( aka Compare & Replace / Elimination ), we have ...
<Before>
C  B = 24  (1)
<After>
5/6 C  5/8 B = 35  (2)
Since question is only asking for C at first, eliminate B as follows:
(1) x 5/8: 5/8 C  5/8 B = 15  (3)
Compare (2) and (3), we subtract (3) from (2) to eliminate B as follows:
(2)  (3): 5/6 C  5/8 C = 20
5/24 C = 20
C = 20 x 24 / 5 = 96
=================================
Trust the above helps.
Do clarify , if any.
Cheers,
Edward

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Registered: 04/21/11 Posts: 627





By: Strawberry (offline) Sunday, May 06 2012 @ 11:15 PM CDT



Strawberry 
thank you... it is very clear..

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Registered: 01/31/09 Posts: 83



