Q&A - PSLE Math

[tianzhu]

Brenda10:

Hi Tianzhu
Thank you for your wonderful picture and explanation. DD said she can understand and also like the presentation. :lol:

Hi Brenda10

Good Morning.

I am happy your dd liked my “masak masak” way of doing maths.

Best wishes

[corneyAmber]

Hifive:

Hi


Maths problem - pls help...

Terry and John went shopping with a total of $198. Terry had $10 more than John. Terry spent 25% as much money as John. After which, he had twice as much money as John.
a) How much money did Terry bring for shopping?
b) How much money had Terry left after shopping?

Kindly help. Thanks in advance!

Hi, I cannot draw pretty models now as I don't hv the tools with me but hope you can understand my solution.

T. |u. | 10. |
J. |u. |
2u + 10 -> 198
2u -> 188
u -> 94
hence Terry has 94+10 =$104 at first

T remainder after spending x : u-x+10= 104-x
J remainder after spending 4x: u-4x = 94- 4x

T remainder = 2x J remainder
So 104-x = 2(94-4x)
7x = 188-104
7x = 84
x = 12

Hence Terry after shopping has 104-12 = $92

[Hifive]

Hi ksi


Thank you for the solution on Terry and John’s question.
Understood part a.
As for part b, I don’t quite get it. Is there an alternative method of solution?

Sorry for taking so much of your time.

Regards

[corneyAmber]

adanial:

Hello, pls help with the question below....thank you



Question 2
Julie had to complete a jigsaw puzzle. On thefirst day, she managed to complete 20% of the puzzle. On the second day she fitted another 60 pc of the puzzle. As a result, the ratio of the number of fitted pieces to the ration of the number of unfitted pieces became 2:5. How many pieces did the jigsaw puzzle consist of ?

20% -> 1/5 fitted, => 7/35

After 60 pieces, ratio becomes 2 out of 7 parts fitted => 10/35

10-7=3
3 parts-> 60
1part -> 20
35 parts -> 700

Hence puzzle is 700 pieces.

Here is the diagram version:
http://i55.tinypic.com/ioferp.jpg\">

[corneyAmber]

Hifive:

Hi ksi


Thank you for the solution on Terry and John's question.
Understood part a.
As for part b, I don't quite get it. Is there an alternative method of solution?

Sorry for taking so much of your time.

Regards

Sorry I am not able to draw the model without my tool so it becomes difficult to visualize, let me try again.

T. |.........u+10-x....| Where x =what Terry spent
J. | u-4x |
Where 4x is what Jerry spent
( 25% = 1/4=> if Jerry spent 4 parts, Terry spent 1 part. So if Jerry spent 100, Terry spent $25 then $25 is 1 part, $100 is 4 parts.)

Based on the model above, Terry has 2 times money left compared to Jerry after both spent so to equal them,

Terry's remainder = 2 x jerry's remainder

So 104 - x = 2(94-4x) then you solve x to get terry's final amount.

Hope this explains better.

[MathIzzzFun]

Hifive:

Hi


Maths problem - pls help...

Terry and John went shopping with a total of $198. Terry had $10 more than John. Terry spent 25% as much money as John. After which, he had twice as much money as John.
a) How much money did Terry bring for shopping?
b) How much money had Terry left after shopping?

Kindly help. Thanks in advance!

Hi

here's the model approach

http://www.flickr.com/photos/62167097@N02/5820245316/in/photostream

cheers.

[PiggyLalala]

MathIzzzFun:

Hifive:

Hi


Maths problem - pls help...

Terry and John went shopping with a total of $198. Terry had $10 more than John. Terry spent 25% as much money as John. After which, he had twice as much money as John.
a) How much money did Terry bring for shopping?
b) How much money had Terry left after shopping?

Kindly help. Thanks in advance!

Hi

here's the model approach

http://www.flickr.com/photos/62167097@N02/5820245316/in/photostream
cheers.

Thanks for the model approach. I have tried to draw the model but not successful. Though my model is same as yours, I failed to see that 1big block = 3u + 10.

[tianzhu]

Hi Hifive


This question touches on simultaneous concept. There are two unknowns and two equations.

Students who are familiar with simultaneous equations may use it solve the problem.

Those who are not, don’t worry too much, you can still get around the problem by solving the equations pictorially. Alternatively, you may also solve it by representing the units and parts by letters of the alphabet or simply using units and parts.

Hope this helps.

Best wishes

http://farm4.static.flickr.com/3079/5819760157_cfb63b3d54_z.jpg\">

[MathIzzzFun]

PiggyLalala:

MathIzzzFun:

[quote=\"Hifive\"]Hi


Maths problem - pls help...

Terry and John went shopping with a total of $198. Terry had $10 more than John. Terry spent 25% as much money as John. After which, he had twice as much money as John.
a) How much money did Terry bring for shopping?
b) How much money had Terry left after shopping?

Kindly help. Thanks in advance!

Hi

here's the model approach

http://www.flickr.com/photos/62167097@N02/5820245316/in/photostream
cheers.

Thanks for the model approach. I have tried to draw the model but not successful. Though my model is same as yours, I failed to see that 1big block = 3u + 10. [/quote]hi

u r welcome

Usually, moving the blocks around will help to \"see\" for example :

http://i52.tinypic.com/2sb3ac8.jpg\">

cheers.

[PiggyLalala]

tianzhu:

Hi Hifive


This question touches on simultaneous concept. There are two unknowns and two equations.

Students who are familiar with simultaneous equations may use it solve the problem.

Those who are not, don’t worry too much, you can still get around the problem by solving the equations pictorially. Alternatively, you may also solve it by representing the units and parts by letters of the alphabet or simply using units and parts.

Hope this helps.

Best wishes

http://farm4.static.flickr.com/3079/5819760157_cfb63b3d54_z.jpg\">

:thankyou: for the alternative 'model' approach. Yours is easy to understand because it is just simultaneous questions in pictorial form.
But not all word problems can use such pictorial simultaneous equations right? How to know which one can, and which one cant?Sorry.. i ask many questions again. Sorry and thanks for your solution and time.