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 By: Tping (offline)  Thursday, June 07 2012 @ 03:25 AM CDT (Read 1699 times)
Tping

Hi, pls help,

Mr Ang bought a total of 200 pears and apples at \$0.20 each.
5 apples were rotten.
He sold the pears at \$0.70 each and the apples at \$0.35 each.
He earned \$58 after selling his fruits.
How many apples did Mr Ang buy?

Thank you!

Junior

Registered: 01/26/12
Posts: 25

 By: echeewh (offline)  Thursday, June 07 2012 @ 09:38 AM CDT
echeewh

Hey there,

Following pls find the worked solution:

Let there be 1u of A and 1p of P
Total Cost of (1u + 1p = 200) A,P = 200 x 0.20 = \$40

Using Number x Value method, we have ...
(converting money to cents)

(1u x 20) + (1p x 20) --> 4000
20u + 20p --> 4000
2u + 2p --> 400 --- (1)

After 5A were found to be rotten, the remaining fruits were sold at a profit of \$58. I.e. these fruits were sold at \$98.

Remaining fruits (in units and parts)
A: (1u - 5)
P: (1p)

[(1u - 5) x 35] + (1p x 70) --> 9800
35u - 175 + 70p --> 9800
35u + 70p --> 9975
1u + 2p --> 285 --- (2)

Given that question is interested in apples (u), we eliminate pears (p) as follows:

(1)-(2): 1u --> 400 - 285 = 115

================================================

Trust this helps.

Cheers,
Edward

Active Member

Registered: 04/21/11
Posts: 627

 By: awyw1201 (offline)  Thursday, June 07 2012 @ 10:05 AM CDT
awyw1201

Another approach using supposition

Cost of all fruits--200 x \$0.20=\$40
No. Of fruits sold---200-5=195
Selling price of all 195 fruits---\$40+\$58=\$98

Suppose all fruits sold were apples, we have
195 x \$0.35=\$68.25
Diff--\$98-\$68.25=\$29.75
Doff btw 1 pear and 1 apple---\$0.70-\$0.35=\$0.35
No. of pears--\$29.75/\$0.35=85
No.of apples at first--195-85+5=115

Regular Member

Registered: 07/08/11
Posts: 87

 By: echeewh (offline)  Thursday, June 07 2012 @ 02:22 PM CDT
echeewh

hi there,

FYI, pls do not take a risk with Guess n Check or Assume ALL method if there is a proper method in solving the problem.. You may not get the full method marks allocated. Hence its to your disadvantage.

Thank you,
Edward

Active Member

Registered: 04/21/11
Posts: 627

 By: awyw1201 (offline)  Friday, June 08 2012 @ 11:12 AM CDT
awyw1201

Quote by: echeewh

hi there,

FYI, pls do not take a risk with Guess n Check or Assume ALL method if there is a proper method in solving the problem.. You may not get the full method marks allocated. Hence its to your disadvantage.

Thank you,
Edward

Hi Edward, as I mentioned in the other thread, there is no deduction of marks for the assumption method. Please do get your facts right before u post. Thanks.

Regular Member

Registered: 07/08/11
Posts: 87

 By: echeewh (offline)  Saturday, June 09 2012 @ 05:03 PM CDT
echeewh

Hey awyw1201 ( to whom it may concern )

I have to agree to disagree ...

Whether or not I get my facts right, yes of course I do. I have seen different marking schemes from about 10 or more schools and encountered situation in which 0 mark is given for Guess& Check / Assume ALL method used in questions where correct / 'proper' method(s) can be used.

Hence, I find its important to share this out with parents and students concerned. Again, whether 0 mark is awarded or not, depends very much on the marker and/or school. My advice is use other correct methods first and take this as a final resort. Exception is to use this method for those typical kind of questions ( where such methods are used ). Again, its always to be 'safe than sorry'. Morale of the story is 'dont take risk' / 'never take chances' like this as it may cause you 0 Method marks, and the opportunity to get a better score that may lead to a better grade.

To All concerned: Pls take this a word of caution and I shall leave this matter in your own hands ( for you to decide ).

Cheers,
Edward

Active Member

Registered: 04/21/11
Posts: 627

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