Q&A - PSLE Math

[tianzhu]

Belle2011:

Dear all,

Source: PSP p6 pg 88.
Ron is a car agent. He receives a fixed salary each month. He also receives a commission of $0.03 fo for every $3 of sales he makes. In a 5 month period, the total value of the cars he sold was $240000. If his total earnings for this period was $8900, find his monthly salary.
(ans: $1300).
Thanks.

cheers,
Belle.

Hi

He receives a commission of $0.03 for every $3 of sales he makes.

3 ------ 0.03
240000 ------ 0.03*(240000/3) ------- 2400

8900 – 2400 -------6500
6500/5 -------1300

Best wishes

[2DMommy]

Please help me with this question.


At the Disney On Ice Concert, 1/15 of the chairs in the indoor stadium were white. 1/4 of the remainder were blue and the rest were red. If there were 4884 red chairs, how many chair were there altogether?

Thks!

[tianzhu]

2DMommy:

Please help me with this question.


At the Disney On Ice Concert, 1/15 of the chairs in the indoor stadium were white. 1/4 of the remainder were blue and the rest were red. If there were 4884 red chairs, how many chair were there altogether?

Thks!

Hi

Draw a rectangle box.
Divide into 60 units.

4 units ----- white (1/15*60)

14 units ------ blue (1/4*56)

42 units ------ red (56-14)

42 units ------ 4884
1 unit ------- 116

60*116 ------- 6960.

Best wishes

[2DMommy]

Thanks TianZhu !


I have another question, is there a easy way to solve this question?

A bag of oranges were shared among some girls. If each girl received 5 oranges, there would be 1 extra orange. If each girl received 6 oranges, there would be 4 oranges short.
a) How many oranges were therein the bag?
b) How many girls were sharing the oranges?

Thks !

[tianzhu]

2DMommy:

Thanks TianZhu !


I have another question, is there a easy way to solve this question?

A bag of oranges were shared among some girls. If each girl received 5 oranges, there would be 1 extra orange. If each girl received 6 oranges, there would be 4 oranges short.
a) How many oranges were therein the bag?
b) How many girls were sharing the oranges?

Thks !

Hi

You're welcome.

You can solve it in two ways

One way is to use a tabulated list (Systematic listing).

The other way is;

Gap ----- (1+4) ------- 5 oranges

Difference in oranges per girl------- (6-5) ------ 1 orange

Number of girls ------- 5/1 -------5

Number of oranges ------- (5*5) + 1 ------ 26
\t
Best wishes

[pixiedust]

TianZhu, the apples and oranges question is killing me. I keep assuming the number must be multiples of 7 and 9.... :stupid: Will wait for solution.


Re: oranges and girls : wow! I like your elegant solution !

[atutor2001]

pixiedust:

...Will wait for solution...

Simply :

Let the number of GROUPs of \"7 apples\" be U
Let the number of GROUPs of \"9 oranges\" be V

1 group of apple costs $4 so cost of all apples is $4U
1 group of orange costs $11 so cost of all oranges is $11V
So 4V + 11V = 999

Total number of apples is 7U (there are 7 apples in each group)
Total number of oranges is 9V (there are 9 oranges in each group)
So 7U + 9V = 1000

To find U & V we can draw model or use simultaneous.

[small]

Different way to solve the question.


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[atutor2001]

small:

Different way to solve the question.


http://farm6.static.flickr.com/5020/5456292860_49335b2630_z.jpg\">

If the question is :

A bag of oranges were shared among some girls. If each girl received 5 oranges, there would be 4 extra oranges. If each girl received 6 oranges, there would be 4 oranges short.

What should I do, using the same method?

[tianzhu]

anneshirleygilbert:

I did it the Guess and Check method and got the answer after 10 guesses!!! Doubt students sitting in PSLE would have the luxury of time to do 10 guesses.

My answer is 343 apples and 657 oranges; but I'm curious and eager to learn your method.

Hi

Hope this helps.

First I’d like to share the thought process for this solution.

A student should be able to recognize that the number of oranges is a multiple of 9 and the number of apples is a multiple of 7.

I started with a group of 100 for ease of calculation as it’s not too difficult to get 72 oranges and 28 apples to form a group of 100 fruits.

Next multiply by 10 to get 1000 fruits.

Work in group of 63 for an increase/decrease of oranges and apples --- for balancing.

Best wishes

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