Questions on percentages - P5

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Questions on percentages - P5

Postby lizawa » Tue Aug 11, 2009 4:01 pm

Hi,

I come across this question in an assessment book and depending on your interpretation, the answers are different. Would you share what you would have interpreted in this case ?

Question:
Wilson's money was 40% of the amount Ann and Betty had. Ann had 4 times as much as Betty. Wilson had $420. Ann spent $294. What percentage of her money did she spend ? Express your answer to 1 decimal place.

Did you get 35% or 58.3% ?

lizawa
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Postby 3greatkids » Tue Aug 11, 2009 4:10 pm

I got 35%.

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Postby dido » Tue Aug 11, 2009 4:39 pm

I've got 35% too.

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Postby 3Boys » Tue Aug 11, 2009 4:49 pm

35%

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Postby lizawa » Tue Aug 11, 2009 4:55 pm

My first attempt is also 35%.

This is the answer from the assessment book.

Wilson -> 40%
Ann-> 4units
Betty -> 1 unit

Ann+ Betty -> 60%
5u = 60%
1u = 60/5 % = 12%

Betty = 12%
Ann = 48%

40% -> $420
48% -> $(420/40) * 48 = $504

% spent = 294/504 *100 = 58.3%


So, this question assumes that the total amount of money = 100%
Ann and Betty get 60%; Wilson 40%.

Doesn't seem too right to me. Is there anyway to rephrase the 1st sentence, such that it means what the answer says ?

lizawa
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Postby Guest » Tue Aug 11, 2009 4:57 pm

Also 35%.

One way to know if the answer is right or not is to substitute backwards both answers and see if you can get $420. The one that cannot will be the wrong answer.
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Postby Guest » Tue Aug 11, 2009 5:02 pm

The first sentence is wrong if it wants the working to be like what you have shown.

It should state:

Wilson has 40% of a sum of money while Ann and Betty together has the other 60%.

If based on original statement, it means that Wilson has 40% of what Ann and Betty (100%) has.
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Postby lizawa » Tue Aug 11, 2009 5:06 pm

ks2me wrote:The first sentence is wrong if it wants the working to be like what you have shown.

It should state:

Wilson has 40% of a sum of money while Ann and Betty together has the other 60%.

If based on original statement, it means that Wilson has 40% of what Ann and Betty (100%) has.


Thanks for this suggestion. This shows that we cannot blindly follow the answers in assessment books.

lizawa
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Postby Guest » Tue Aug 11, 2009 5:41 pm

lizawa wrote:
ks2me wrote:The first sentence is wrong if it wants the working to be like what you have shown.

It should state:

Wilson has 40% of a sum of money while Ann and Betty together has the other 60%.

If based on original statement, it means that Wilson has 40% of what Ann and Betty (100%) has.


Thanks for this suggestion. This shows that we cannot blindly follow the answers in assessment books.


You are welcome. It is quite often we come across publications with errors. If you want to take another step, you can alert them then they can rectify this in their next print.
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