Q&A - P5 Math

[Jamesbond]

tianzhu:

Jamesbond:

During a fund raising project, class5A raised 2/3 as much money as the total amount raised by classes 5B and 5C. Class 5B raised 1/5 as much money as the total amount raised by class 5A and 5C.

a) what fraction of the funds was raised by class5A?
b) Class 5B raised $104 less than class 5C. How much money did class 5C raise?
Pl help using model or units....Thanks.

Hi

You may present the solution in various forms, MD, using units in tabulated form or commonly using ratios.

At this juncture, maybe, the topic on ratios has not been covered in P5.

Due to time constraints, I’ll just give you some pointers for you to present it in MD or units.

A : (B+C) ------ 2 : 3 (5) -------12:18 (30)

B : (A+C) ------- 1:5 (6) -------5:25 (30)

Make the total number of units the same.

A ------ 12 units

B ------- 5 units

C ------- 13 units

a)Fraction of the funds was raised by class5A -------- 12/30 ------ 2/5

b)8 units ------ 104
1 unit ------13
Amount of money raised by Classs C ------ 13*13 ------- 169

Best wishes

:? My ds finds it hard to understand.... :imdrowning:

[tianzhu]

Jamesbond:

My ds finds it hard to understand....

Hi

Questions of such genre can be solved easily using ratios.

The key point is to make the number of units the same in both scenarios.

Perhaps, your ds found it difficult because he hasn’t learned ratios yet.

I’ll find some time to present in MD at a later time, maybe tomorrow.

Best wishes

[MathIzzzFun]

Jamesbond:

tianzhu:

[quote=\"Jamesbond\"]During a fund raising project, class5A raised 2/3 as much money as the total amount raised by classes 5B and 5C. Class 5B raised 1/5 as much money as the total amount raised by class 5A and 5C.

a) what fraction of the funds was raised by class5A?
b) Class 5B raised $104 less than class 5C. How much money did class 5C raise?
Pl help using model or units....Thanks.

Hi

You may present the solution in various forms, MD, using units in tabulated form or commonly using ratios.

At this juncture, maybe, the topic on ratios has not been covered in P5.

Due to time constraints, I’ll just give you some pointers for you to present it in MD or units.

A : (B+C) ------ 2 : 3 (5) -------12:18 (30)

B : (A+C) ------- 1:5 (6) -------5:25 (30)

Make the total number of units the same.

A ------ 12 units

B ------- 5 units

C ------- 13 units

a)Fraction of the funds was raised by class5A -------- 12/30 ------ 2/5

b)8 units ------ 104
1 unit ------13
Amount of money raised by Classs C ------ 13*13 ------- 169

Best wishes

:? My ds finds it hard to understand.... :imdrowning:[/quote]hope this helps..

http://i45.tinypic.com/24y5n4l.png\">

as mentioned by tianzhu, it is more efficient to solve such questions using ratio method.

cheers.

[Jamesbond]

True I agree.....Thanks for ur help mathizzfun..... :salute:

[Xiao Hu]

Jamesbond:

tianzhu:

[quote=\"Jamesbond\"]During a fund raising project, class5A raised 2/3 as much money as the total amount raised by classes 5B and 5C. Class 5B raised 1/5 as much money as the total amount raised by class 5A and 5C.

a) what fraction of the funds was raised by class5A?
b) Class 5B raised $104 less than class 5C. How much money did class 5C raise?
Pl help using model or units....Thanks.

Hi

You may present the solution in various forms, MD, using units in tabulated form or commonly using ratios.

At this juncture, maybe, the topic on ratios has not been covered in P5.

Due to time constraints, I’ll just give you some pointers for you to present it in MD or units.

A : (B+C) ------ 2 : 3 (5) -------12:18 (30)

B : (A+C) ------- 1:5 (6) -------5:25 (30)

Make the total number of units the same.

A ------ 12 units

B ------- 5 units

C ------- 13 units

a)Fraction of the funds was raised by class5A -------- 12/30 ------ 2/5

b)8 units ------ 104
1 unit ------13
Amount of money raised by Classs C ------ 13*13 ------- 169

Best wishes

:? My ds finds it hard to understand.... :imdrowning:[/quote]Hi Tianzhu, MathIzzzFun, Jamesbond,

Another method is to use the fraction method, as given in the question.

(a) Class5A raised ->2/5 of Total ( A ->2u, B+C -> 3u, so total is 5u).

(b)Class5B raised ->1/6 of Total
So Class5C raised =1-2/5-1/6=13/30 of Total

5B-5C =13/30-1/6=8/30 of Total->$104.

From here onwards, same working as Tianzhu's.

Thanks, and hope it helps,
Xiaohu

[Jamesbond]

Thx for ur help Xian Ho.

[Jamesbond]

There were 4 times as many as red pens as blue pens in a box. 415 red pens and 46 blue pens were removed from the box. As a result, the number of blue pens became 3 times as many as red pens. How many blue pens were there in the beginning?

Pl help.

[Jamesbond]

quekcc:

Jamesbond:

There were 4 times as many as red pens as blue pens in a box. 415 red pens and 46 blue pens were removed from the box. As a result, the number of blue pens became 3 times as many as red pens. How many blue pens were there in the beginning?

Pl help.

http://i50.tinypic.com/63sqp3.jpg\">

Thank you quekcc for ur help.

[sokk]

Hi,


Have a question on average that I need help with. Thanks !

Bin has $30 more than Ron.
Wei has 4/3 of the average of what Ron and Bin have.
The average amount that Bin and Wei have is 1.5 of Ron's money.
How much money does Wei have?

Thanks !

[janicelhl]

Hi, can someone help to solve


The number of shells in Box A was 12 more than that in Box B. When 96 shells were transferred from Box A to Box B, the number of shells in Box B became 3 times that of Box A. Find the total number of shells in Box A at first.

Thank you