Q&A - PSLE Math

[corneyAmber]

I agree with you mathizzzfun about moving the blocks around and most times even hand drawn pictures can still roughly deduce. However in this case, not so clear so under exam conditions, if there are no perfect tools to produce the diagrams perfectly, it would be difficult to deduce the 10 per your diagram. Maybe you can help to think further how it can be deduced if diagrams cannot be perfectly drawn. thank you.

[tianzhu]

adanial:

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


Question 1
Loyang electronic store sold television sets, fans and washing machines.
2/5 of the items in the store were television sets. 12.5% of the remainder were fans and the rest were washing machines. During a sale held in december, the number of televsion sets sold to the number of fans sold to the number of washing machnes sold was 3:2:4. Altogether 3/4 of the items in the store were sold and $34070 was collected from the sale of all the items.
The table below shows teh average selling price of the 3 items in loyang electronic store :

TV set - $1350
Fan - $102
Washing m/c - $640

How many washing machines were on sale at first ?

Hi

Please help to confirm the numbers which were underlined.

Best wishes

[tianzhu]

PiggyLalala:

: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.

Hi PiggyLalala

You're welcome.

Yes, you’re correct to say that one cannot apply SE to all word problems.

MD is one of many problem solving heuristics in the primary maths syllabus, it’s not the only way.

You may use “simultaneous concept” to questions involving two variables scenarios.

Best wishes

[Hifive]

Hi ksi, MathIzzzFun, PiggyLalala and tianzhu


Many thanks for taking your precious time to help me in the understanding of the Maths problem sum.

Really feel so bless for the help from all the experts here.

Have a nice day ahead!

[adanial]

tianzhu:

adanial:

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


Question 1
Loyang electronic store sold television sets, fans and washing machines.
3/5 of the items in the store were television sets. 12.5% of the remainder were fans and the rest were washing machines. During a sale held in december, the number of televsion sets sold to the number of fans sold to the number of washing machnes sold was 3:2:4. Altogether 3/4 of the items in the store were sold and $34070 was collected from the sale of all the items.
The table below shows teh average selling price of the 3 items in loyang electronic store :

TV set - $1350
Fan - $102
Washing m/c - $640

How many washing machines were on sale at first ?

Hi

Please help to confirm the numbers which were underlined.

Best wishes

changed 2/5 to 3/5 ** thanks

[corneyAmber]

http://i55.tinypic.com/35bw65i.jpg\">

[tianzhu]

adanial:

tianzhu:

[quote=\"adanial\"]Hello, pls help with the question below....thank you


Question 1
Loyang electronic store sold television sets, fans and washing machines.
3/5 of the items in the store were television sets. 12.5% of the remainder were fans and the rest were washing machines. During a sale held in december, the number of televsion sets sold to the number of fans sold to the number of washing machnes sold was 3:2:4. Altogether 3/4 of the items in the store were sold and $34070 was collected from the sale of all the items.
The table below shows teh average selling price of the 3 items in loyang electronic store :

TV set - $1350
Fan - $102
Washing m/c - $640

How many washing machines were on sale at first ?

Hi

Please help to confirm the numbers which were underlined.

Best wishes

changed 2/5 to 3/5 ** thanks[/quote]Hi

Please check your source again. I think some numbers in the original question are offside.

I did a quick check, you’re likely to find a solution if the question is revised as such.

Loyang Electronic Store sold television sets, fans and washing machines.

1/3 of the items in the store were television sets. 25% of the remainder was fans and the rest were washing machines. During a sale held in December, the number of television sets sold to the number of fans sold to the number of washing machines sold was 3:2:4. Altogether 3/4 of the items in the store were sold and $34070 was collected from the sale of all the items.

The table below shows the average selling price of the 3 items in Loyang Electronic Store :

TV set - $1350
Fan - $102
Washing m/c - $640

How many washing machines were on sale at first ?

Best wishes

[MathIzzzFun]

ksi:

I agree with you mathizzzfun about moving the blocks around and most times even hand drawn pictures can still roughly deduce. However in this case, not so clear so under exam conditions, if there are no perfect tools to produce the diagrams perfectly, it would be difficult to deduce the 10 per your diagram. Maybe you can help to think further how it can be deduced if diagrams cannot be perfectly drawn. thank you.

hi

models need not be rectangular or square blocks, it can be in any form as long as the model correctly represent the question. For eg, we can use stars or moons which the students are exposed to in lower primary. So, it really does not matter whether the drawing is to scale or not but it is important that if the relation is for variable is 1 : 3 and 2: 5 for another variable, then the student must have two different sized blocks or two different shapes to represent these variables. For eg. in the Terry and John question,

http://i55.tinypic.com/fub7lh.jpg\">

cheers.

[corneyAmber]

MathIzzzFun:

ksi:

I agree with you mathizzzfun about moving the blocks around and most times even hand drawn pictures can still roughly deduce. However in this case, not so clear so under exam conditions, if there are no perfect tools to produce the diagrams perfectly, it would be difficult to deduce the 10 per your diagram. Maybe you can help to think further how it can be deduced if diagrams cannot be perfectly drawn. thank you.

hi

models need not be rectangular or square blocks, it can be in any form as long as the model correctly represent the question. For eg, we can use stars or moons which the students are exposed to in lower primary. So, it really does not matter whether the drawing is to scale or not but it is important that if the relation is for variable is 1 : 3 and 2: 5 for another variable, then the student must have two different sized blocks or two different shapes to represent these variables. For eg. in the Terry and John question,

http://i55.tinypic.com/fub7lh.jpg\">

cheers.

Agree, so using this explanation, can see the concept better. If the concept is not grasped, the 'shifting of blocks' method will reveal the concept if drawn to scale.

[corneyAmber]

tianzhu:

adanial:

[quote=\"tianzhu\"]
Hi

Please help to confirm the numbers which were underlined.

Best wishes

changed 2/5 to 3/5 ** thanks

Hi

Please check your source again. I think some numbers in the original question are offside.

I did a quick check, you’re likely to find a solution if the question is revised as such.

Loyang Electronic Store sold television sets, fans and washing machines.

1/3 of the items in the store were television sets. 25% of the remainder was fans and the rest were washing machines. During a sale held in December, the number of television sets sold to the number of fans sold to the number of washing machines sold was 3:2:4. Altogether 3/4 of the items in the store were sold and $34070 was collected from the sale of all the items.

The table below shows the average selling price of the 3 items in Loyang Electronic Store :

TV set - $1350
Fan - $102
Washing m/c - $640

How many washing machines were on sale at first ?

Best wishes[/quote]Hi tianzhu,

Can you check if my solution above is correct based on the revised fraction by adanial? Thanks.