Q&A - P3 Math

[PiggyLalala]

Length:XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX

New L :XXXXXXXXXX XXXXXXXl<------- 2m -------->
Breadth:XXXXXXXXX
New B : XXXXXXXXX<-80cm->l

When drawing the model, one has to rememeber the hidden information in this question, one has to ensure that the new Length and breath must be of the same length in the model.

therefore 2 units = 2m + 80 cm = 200 cm + 80 cm = 280 cm
1 unit = 140 cm
Diamension of the rectangular table is 420 cm by 140 cm

[Charnic]

Pls help me on the P3 maths:

Tin A, Tin B and Tin C are required to paint a complete wall. If only Tin A is used, we are short of 7litres. If only Tin B is used, we are short of 5 litres. If only Tin C is used, we are short of 3 litres. How many litres of paint is required to paint a complete wall? TIA.

[smartmummy]

CNS:

Pls help me on the P3 maths:

Tin A, Tin B and Tin C are required to paint a complete wall. If only Tin A is used, we are short of 7litres. If only Tin B is used, we are short of 5 litres. If only Tin C is used, we are short of 3 litres. How many litres of paint is required to paint a complete wall? TIA.

A *** ```````
B *****``````
C *******````

In A length of * s is equal to length of `es in C.So Tin A contains 3 litres.Now we know Total length is 10 litres.So B is 10-5=5 Litres.C contains 10-3 is 7 litres.So 3+5+7=15 litres required to paint a complete wall.
Sorry I couldn't draw model and mark the length.Hope You understand.

[Charnic]

Sorry, I still could not see why Tin A contains 3 litres. Pls advise. Thanks

[smartmummy]

Hi CNS!

lenght of * =how many litres in the respective Tin
length of ` =how many litres sort for to paint the complete wall
X+7=Y+3, I think, obiviously X=3, Y=7.
If you draw the model manually u can see.

If we do by algebra method there are many possible answers,but for primary1/2 they don’t have algebra method.So just guess.

[corneyAmber]

Hi CNS and concerned_parent, the key in this question is that all 3 cans of paint must be used for the wall.


http://i53.tinypic.com/2418tch.jpg\">

[smartmummy]

Hi cns!


sorry for my answer.very tricky question!

[corneyAmber]

concern_parent:

Hi cns!


sorry for my answer.very tricky question!

yes I agree this question is indeed tricky.

[jedamum]

P3 Math?! even with the solution, i am still seeing stars....:faint:

[PiggyLalala]

ksi:

Hi CNS and concerned_parent, the key in this question is that all 3 cans of paint must be used for the wall.


http://i53.tinypic.com/2418tch.jpg\">

Thank you for the solution.
But why why is 7-u+3-u --->5?
I do not quite understand this step.