Q&A - PSLE Math

[ADoc]

tisha:

Thank you ADoc for the solution.

Hi Tisha! You're most welcome!
cheers!

[ozora]

have a question to ask ;

Jane bought 12 roses and 9 lilies for her mother. Each rose cost $2.50 less than each lily. If the total cost of the lilies was $0.50 more than the total cost of the roses, how much did Jane spend on the flowers altogther?

[tianzhu]

Emelyn:

Best wishes.
Oopss... sorry.... for not checking the earlier discussion.
Thanks for explaining it again.

Hi

You're welcome.

Best wishes

[tianzhu]

Belle2011:

Dear tian-zhu,

Thank very much for sharing another way of presenting the solution.
I was stuck with \"After B took 5/6 of the remaining tin of cookies...\".
So 5/6 * 1/6 = 5/36.
I am thinking \"my gosh! 5/36, how to draw the model...\".
Anyway, I am trying to reduce the number of 5 mark problem sums which I can't solve to as low as possible and you have been helping me all along.
Once again, thanks a lot.
Cheers,
Belle.

Hi

You're welcome.

Best wishes

[tianzhu]

LaiHeng:

have a question to ask ;

Jane bought 12 roses and 9 lilies for her mother. Each rose cost $2.50 less than each lily. If the total cost of the lilies was $0.50 more than the total cost of the roses, how much did Jane spend on the flowers altogther?

Hi

A quick one

9*2.5 -------22.5

12 units + 0.5 --------- 9 units + 22.5 (total cost of the lilies was $0.50 more than the total cost of the roses)

3 units -------- 22
21 units -------154

(154+22.5) -------176.5

Jane spent $176.50 on the flowers.

Best wishes

[small]

ADoc:

LaiHeng:

[quote=\"small\"]

Hi,

HTH..


The key step is to calculate Joe's percentage. Given that Amos's salary is 20% less than Joe's.

80% of Joe = 120% of Steve
100% of Joe = 150% of Steve

Steve = 100% (10 Units)
Amos = 120% (12 Units)
Joe = 150% (15 Units)

37 Units = 2220
1 Unit = 60
12 Unit = 720

or
370% = 2220
1% = 6
120% = 720.

to anyone,
can someone enlighten how 100% of Joe = 150% of Amos?
I can't catch any clues on how to derive it.

Hi, I believe there was a typo error in the answer above.
It should be 100% of Joe = 150% of Steve instead of Amos.

Hope this clarifies.
cheers
ADoc[/quote]

Hi LaiHeng,

My apologies for the typo error. :stupid: It should be 80% of Joe = 120% of Steve.



Many thanks to Adoc for pointing out my error. :celebrate: :celebrate:

[small]

is_me_lblue:

is_me_lblue:

Hi,


I am stuck again.

Amos'salary is 20% more than Steve's but 20% less than Joe's. If their total salary is $2220,find Amos's salary.

I always get the answer of 740 but answer given is 720.

Thank you

Small,

Thank you, I not so good in math so have to learn together with my son.

Hi,

Plese refer my revised solution. Apologies for the typo error in my ealier post

http://farm6.static.flickr.com/5138/5488155395_fe1c7f694a_b.jpg\">

[spunky]

Firsly, I think do you have a issue with deciding who is the 100%? That is usually on eof the common problem.Maybe you can send me ur solution then I can help u diagnose why u arrive at $740


Secondly, remember that Ratio, percentage and fraction can be used to solve a problem sum despite the question being a % question.

Solution (Ratio method) which is what I would usually use for this type of questions.


A : S
120 : 100
6 : 5
x 2 x 2
J : A
100 : 80
5 : 4
x 3 x 3

J : A : S
15 : 12 : 10

37 units --> 2220
1 unit --> 2220 ÷ 37
--> 60
12 units --> 60 x 12
--> $720

small:

is_me_lblue:

[quote=\"is_me_lblue\"]Hi,

I am stuck again.

Amos'salary is 20% more than Steve's but 20% less than Joe's. If their total salary is $2220,find Amos's salary.

I always get the answer of 740 but answer given is 720.

Thank you

Small,

Thank you, I not so good in math so have to learn together with my son.

Hi,

Plese refer my revised solution. Apologies for the typo error in my ealier post

http://farm6.static.flickr.com/5138/5488155395_fe1c7f694a_b.jpg\">

8)[/quote]

[ozora]

tianzhu:

LaiHeng:

have a question to ask ;

Jane bought 12 roses and 9 lilies for her mother. Each rose cost $2.50 less than each lily. If the total cost of the lilies was $0.50 more than the total cost of the roses, how much did Jane spend on the flowers altogther?

Hi

A quick one

9*2.5 -------22.5

12 units + 0.5 --------- 9 units + 22.5 (total cost of the lilies was $0.50 more than the total cost of the roses)

3 units -------- 22
21 units -------154

(154+22.5) -------176.5

Jane spent $176.50 on the flowers.

Best wishes

thanks .. is really clear explanation

[ozora]

ADoc:

LaiHeng:

[quote=\"small\"]

Hi,

HTH..


The key step is to calculate Joe's percentage. Given that Amos's salary is 20% less than Joe's.

80% of Joe = 120% of Amos
100% of Joe = 150% of Amos

Steve = 100% (10 Units)
Amos = 120% (12 Units)
Joe = 150% (15 Units)

37 Units = 2220
1 Unit = 60
12 Unit = 720

or
370% = 2220
1% = 6
120% = 720.

to anyone,
can someone enlighten how 100% of Joe = 150% of Amos?
I can't catch any clues on how to derive it.

Hi, I believe there was a typo error in the answer above.
It should be 100% of Joe = 150% of Steve instead of Amos.

Hope this clarifies.
cheers
ADoc[/quote]thanks to everyone and Adoc. It cleared my doubts.