Q&A - PSLE Math

[bobsg01]

Thank you ksi. :rahrah:

[bobsg01]

P6 Volume question.


Thanks for any help provided.

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[corneyAmber]

bobsg01:

P6 Volume question.


Thanks for any help provided.

http://i53.tinypic.com/25k1zpf.jpg\">

1 l = 1000c cubic cm

tank = 16x10x24 = 3840 cubic cm
oil = 1.28 l = 1.28 x 1000 = 1280 cubic cm
(a) fraction of oil = 1280 / 3840 = 1/3

(b) 2/3 of tank needs to be filled to be completely filled.

Hence amt of oil to fill tank completely
= 2/3 x 3840
= 2560 cubic cm
= 2.56 litres

Alternatively,
1 part -> 1.28 litres
2 parts -> 1.28 x 2 = 2.56 litres

[corneyAmber]

bobsg01:

Thank you ksi. :rahrah:

you are welcome.

stary, you are welcome too..

[Kloggy]

Hi,


Need help on following 2 qns from Maha Bodhi, 2010, Prelim.

1) Paper 2, qn 6
Apples cost 40 cents each and Pears cost 60 cents each.
Mrs Gopal and Mrs Ari went to the supermarket. Both women decided to spend all their money on either apples or pears and they would not buy the same fruit.
If Mrs Gopal bought only pears, she would have 9 more fruit than Mrs Ari.
If she bought only apples, she would have 41 more fruit than Mrs Ari.
How much more money has Mrs Gopal than Mrs Ari ?

2) Paper 2, qn 13.
Diagram shows two containers X and Y.
Container X is being filled by tap B
Container Y is being filled by tap A.
Container X has base of 25 cm by length (which is unknown)
Container Y has base of 50 cm by 45 cm

Here is the qn :
In every minute, three times as much water flows out of Tap A as Tap B into two empty containers, X and Y.
After 20 minutes, container X is 2/5 filled with water and the height of the water level in container X is the same as that of container Y.
(a) what is the length of the base of container X?
(b) How many litres of water can container X hold ?

I managed to find the answer to (a), which is 30 cm.
But how to do part (b) ? (Ans : 56.25)

Pls help !!!
Thanks.

[stary]

Kloggy:

Hi,


Need help on following 2 qns from Maha Bodhi, 2010, Prelim.

2) Paper 2, qn 13.
Diagram shows two containers X and Y.
Container X is being filled by tap B
Container Y is being filled by tap A.
Container X has base of 25 cm by length (which is unknown)
Container Y has base of 50 cm by 45 cm

Here is the qn :
In every minute, three times as much water flows out of Tap A as Tap B into two empty containers, X and Y.
After 20 minutes, container X is 2/5 filled with water and the height of the water level in container X is the same as that of container Y.
(a) what is the length of the base of container X?
(b) How many litres of water can container X hold ?

I managed to find the answer to (a), which is 30 cm.
But how to do part (b) ? (Ans : 56.25)

Pls help !!!!!
Thanks.

Base area of Container Y -> 50 x 45 = 2250 cm2
Base area of Container X -> 2250/3 = 750 cm2
Length of Container X -> 750/25 = 30 cm(a)

Time to fill Container X -> 5/2 x 20 = 50 min
Height -> 3/2 x 50 = 75cm
Water to fill Container X -> 25x30x75 = 56250 cm3 = 56.25 litres(b)

[tianzhu]

Kloggy:

1) Paper 2, qn 6
Apples cost 40 cents each and Pears cost 60 cents each.
Mrs Gopal and Mrs Ari went to the supermarket. Both women decided to spend all their money on either apples or pears and they would not buy the same fruit.
If Mrs Gopal bought only pears, she would have 9 more fruit than Mrs Ari.
If she bought only apples, she would have 41 more fruit than Mrs Ari.
How much more money has Mrs Gopal than Mrs Ari ?

Hi

This question has been discussed in one of the earlier posts.

Please refer to the solution from kancheongmum.

After reading Tianzhu post, lead me to solve this question using this method which is not new. The question of Tom spend $40 per day and Mary spend $80 per day and Mary would have $500 left when Tom has spent all his money .......

Apples : Pears ---- 40:60 ---- 2:3

1st case Ari spent 2/3 of Gopal 2nd case Ari spent 3/2 of Gopal
equal fraction 2/3 = 6/9 and 3/2 = 6/4

Gopal ()()()()()()()()() $5.40
Ari ()()()()()()

Gopal ()()()() $16.40
Ari ()()()()()()


9u + $5.40 = 4u + $16.40
5u ---- $11
1u ---- $2.20
Gopal money more than Ari by ---- 3u + $5.40 = (3 x $2.20) + $5.40
= $12

Best wishes

[bobsg01]

Many thanks to ksi.


:hi5:

[benleetube]

Hi all, everyone. Can you guys help me with this question? I am not sure if this question have been posted before, but here is it:


At 9 a.m., John was cycling from point A to point B. At the same time, Mary was cycling from point B to point A using the same route as John. Cycling at a speed of 4km/h faster than Mary, John would pass Mary 300m away from the midpoint.

(A) what time did they pass each other?

(B) if John took another 3 minutes to reach point B, what time would Mary reach point A?

(Appeared in catholic high SA2(prelim) paper as question 15)

Thanks in advance.

[corneyAmber]

bobsg01:

Many thanks to ksi.


:hi5:

:welcome: :hi5: