Q&A - PSLE Math

[tianzhu]

kavisuresh:

3. Aaron and kumar took part in a 24km marathon. Aaron ran half the distance at a speed of 10km/h and jogged the rest of the way at a speed of 8km/h. Kumar ran half of his total time at 12km/h and jogged the rest of the time at 6km/h. If they started the marathon at 8am, at what time would each of them finish ?

Hi

Aaron
12/10 ------ 1.2h
12/8 ------ 1.5h

Total time ------2.7 h -------2h 42 min

Kumar
Speed -----12:6 -------2:1
Distance ----- 2:1

3 units ------24km
1 unit ------8km

Kumar ------ 16/12 ------ 1h 20 min
8/6 ------ 1h 20min

Total time ------ 2h 40 min

Best wishes

[tianzhu]

kavisuresh:

1. A rectangular tank with dimesnions 130cm by 100cm by 210cm was 30% filled with water. 8 identical pails of water, completely filled , were scooped out of it from it and this resulted in a drop of the water level to 38cm. The remaining amt of water was transferred into a cubical tank containing 39l of water. The water was then drained out through a tap at the bottom of the cubical tank at 13l per minute. a) what is the capacity of each pail ? b) How long did it take to drain water from cubical tank completely ?

Hi

Volume of water in rectangular tank ------- 0.3(130*100*210) ------- 819000

Amount of water left ------- 130*100*38 ------- 494000

Difference in volume ------- 819000 – 494000 ------- 325000

Volume or capacity of 1 pail -------325000/8 ------ 40625

Change 494000 cubic cm to litres which is 494 litres

(494+39)/131------- 41 mins.

Best wishes

[TENNISMOM]

After looking at the Henry Park Prelims Math 2011 Paper 2, I felt that it was set at a rather difficult level. I am thinking this might be done in order to offset the Paper 1 which was super easy. Any views anyone? My DD was quite disheartened by Paper 2…

[kavisuresh]

Thank you for the quick replies.

[htn]

Hi Vanilla Cake


Can u teach me how to solve nan hua prelim paper 2 Q16 b?
TIA

[zsqchx]

Please help to solve this question. Thanks


On Sunday, bags in a shop were sold at $10 each. On Monday, the price of bags was reduced and the number of bags sold increased by 50 % while the total amount of money collected increased by 5%. Find the price of a bag sold on Monday.

[tianzhu]

jeysri72:

Hi,


Can anyone give a clear explanation on how to solve the problem in RGS Prelim Maths 2011 Paper 2 Question 18?
The question is: Beaker A and Beaker B contain some water. If 46.5 ml of water is drained out from Beaker A, the volume of the water in beaker A will be 60% that of the water in Beaker B. If 32.5 ml of water is drained out from Beaker B will be 85% that of the water in Beaker A. What is the total volume of water in Beaker A and Beaker B?
Ans:290.5 ml

Hi

To get the answer of 290.5ml, 32.5ml should be read as 35.2ml.

Hope this helps.

Best wishes.

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[P5G]

TENNISMOM:

After looking at the Henry Park Prelims Math 2011 Paper 2, I felt that it was set at a rather difficult level. I am thinking this might be done in order to offset the Paper 1 which was super easy. Any views anyone? My DD was quite disheartened by Paper 2...

Hi Auntie TENNISMOM,

I found the paper 2 quite OK except for the last 2 questions.


However for all the Science papers, I am struggling and depressed that I could not do some many MCQ and OE questions!

[tianzhu]

zsqchx:

Please help to solve this question. Thanks


On Sunday, bags in a shop were sold at $10 each. On Monday, the price of bags was reduced and the number of bags sold increased by 50 % while the total amount of money collected increased by 5%. Find the price of a bag sold on Monday.

Hi

Number of bags sold

Mon : Sun ----- 3:2

Using Number*Value Method or MD.

Sun
Sold ------20 units

Mon
Sold ------21 units (increased by 5%)

21/3 ------7

Price of bag on Mon -------$7

Best wishes

[P5G]

htn:

Hi Vanilla Cake


Can u teach me how to solve nan hua prelim paper 2 Q16 b?
TIA

Hi Uncle/Auntie htn,

For (16b), you just need to add the two areas together then use the volume
of water divide by the total area as follows:

500 + 300 = 800 cm2

6000/800 = 7.5 cm