Q&A - PSLE Math

[Tnsp]

Tap A flows at a rate of 2,100 ml/min while Tap B flows at a rate of 2,500 ml/min. Both taps were turned on at the same time to fill a tank with dimensions 50cm by 40cm by 30 cm. After 5 mins., the plug at the bottom of the tank is removed, with the two taps still running. If the water is drained at the rate of 600 ml/min, what is the water level 2 mins. after the plug is removed ?


[MGS Prelim 2008 Maths B2 Q47]

Key question: which is L, B and H ? The question did not specify.

Thanks !

[Tang]

Tnsp:

Tap A flows at a rate of 2,100 ml/min while Tap B flows at a rate of 2,500 ml/min. Both taps were turned on at the same time to fill a tank with dimensions 50cm by 40cm by 30 cm. After 5 mins., the plug at the bottom of the tank is removed, with the two taps still running. If the water is drained at the rate of 600 ml/min, what is the water level 2 mins. after the plug is removed ?


[MGS Prelim 2008 Maths B2 Q47]

Key question: which is L, B and H ? The question did not specify.

Thanks !

We were told to assume that the dimensions given are L, B and H. For your information please.

[Maths Monster]

delete

[Tnsp]

Maths Monster:

If nothing is stated, they should be in the order L = 50cm, B = 40 cm and H = 30cm.

Is this from text book ? SEAB ?

I am the question wants to test the steps as you have worked out above.
But why need the 'assumption' ? I felt the question should be clearer upfront.

Thanks !

[Tang]

Tnsp:

Maths Monster:

If nothing is stated, they should be in the order L = 50cm, B = 40 cm and H = 30cm.

Is this from text book ? SEAB ?

I am the question wants to test the steps as you have worked out above.
But why need the 'assumption' ? I felt the question should be clearer upfront.

Thanks !

May be it is an international standard!

[ctct61t]

Good source, I keep it for future reference.


CoffeeCat is really a very good and responsible teacher.
He give me very useful suggestion for my girl’s math study.
My girl is in P2. As a kiasu mother, I try to let her enroll for some olympiad maths training, and did not relised that will kill her interested. CoffeeCat give me his opinion on kid’s maths study, and point out the right way to let children to go for maths study. Woo, a really good responsible person…Thank you.

[mummyjoyce]

Very good links… must print out and let my DD practise! Thank you for doing this.

[meeyah]

Thanks for sharing…The problem sums are really difficult. Can someone sharing the workings on how they arrive the answers? Hehehee…not sure whether I am being greedy to ask for more.

[CoffeeCat]

I believe the above 3 replies was shifted from this thread

Q&A - PSLE Maths - Highlights ONLY
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=9494

meeyah:

Thanks for sharing...The problem sums are really difficult. Can someone sharing the workings on how they arrive the answers? Hehehee...not sure whether I am being greedy to ask for more.

I think you need to specify the problems you have trouble with and hopefully some math guru can add on in that thread for future reference. The 2009 questions are being done countless times in the thread i specified in the post there.

[tianzhu]

[quote]Well,ratio problems are supposed to be solved by ratio.I love using ratio but i'm always stuck at challenging questions that involve ratio.One quick(inaccurate) example is this: The marbles that A and B has is in the ratio 6:7. Then,124 marbles were added to the total and the ratio became 2:3.How many marbles were there at first? These kind of questions are common and its almost impossible to solve using model. If your dd knows how to use ratio to solve such challenging problems,then your dd should be alright if she wants to use model now as she still have the \"skills\" to apply the ratio method if she needs it.However,if she cannot solve using ratio,then she may face difficulty with the challenging questions.[/quote]
Hi

I picked up this quote from the thread, Tips for improving in PSLE. It was from a member called livewith_vanilla.

I think the question she posed is a pretty interesting one, it involves two changed quantities, but the number(124) involved in the transaction is lumped into one lot instead of two different portions.

The marbles that A and B has is in the ratio 6:7. Then,124 marbles were added to the total and the ratio became 2:3.How many marbles were there at first?

Have fun.
Best wishes