Q&A - PSLE Math

[corneyAmber]

angela:

Hi,


anyone can advise?

Example:

John took 2 hour to travel from home to school and took 2 hour 30 minutes to travel from school to playground. What was the time taken that John taken to travel for the whole journey?

The answer is 4 hour 30 minutes but how to show working.

2 hour + 2 hour = 4 hours

4 hours 30 minutes. (correct?)

Thks

Is this a P6 question? Time can be expressed in fractions.
If one feels the need to show working, then 2+2 1/2 = 4 1/2 = 4 hrs 30 mins.

[corneyAmber]

Q12

-> In the figure, the shaded portion shows a 3m wide cemented walkway in a rectangular field of length 40cm and breadth 20m. Besides the walkway, rest of the rectangular field is covered with grass.
(a) Find the area of the walkway. (why is the answer 20m x 3m?)
(b) Find the area of the field that is covered with grass.

I cannot find the diagram on the net, can you furnish the diagram?

[corneyAmber]

Q14 -> If Ahmad and Ben work together, they can complete a job in 12 days. If Ahmad and Ben worked together for 3 days, followed by Ben who worked alone for the next 5 days, they can finish 5/12 of the job. How many days will each of them need to complete the job if they were to work alone?


12 days -> 12 parts of job
3 days -> 3 parts of job

Ben completed another 2 parts in 5 days
=> He completes 1 part in 2.5 days
12 parts-> 12*2.5 = 30 days
Hence Ben will complete the same job alone in 30 days.

Since Ben does 1 part in 2.5 days
=>1 day he does 0.4 part, 3 days he does 1.2 part of job
=> Ahmad does (3-1.2)=1.8 part of job in 3 days
=> Ahmad does 0.6 part of job in 1 day
=>Ahmad does 12 parts in (1/0.6)*12 = 20 days

[Vanilla Cake]

ksi:

Q12

-> In the figure, the shaded portion shows a 3m wide cemented walkway in a rectangular field of length 40cm and breadth 20m. Besides the walkway, rest of the rectangular field is covered with grass.
(a) Find the area of the walkway. (why is the answer 20m x 3m?)
(b) Find the area of the field that is covered with grass.

I cannot find the diagram on the net, can you furnish the diagram?

Hi ksi,
Here's the http://www.orlesson.org/orp/09Ma/2009-P6-Math-SA1-AiTong.pdf and pls go to page 19 for Q12 which is from Ai Tong 2009 P6 SA1 Paper 2 set on 14 May 2009.

[Dharma]

abc_parent:

May I know how to solve the following , gurus?


Q14
-> If Ahmad and Ben work together, they can complete a job in 12 days. If Ahmad and Ben worked together for 3 days, followed by Ben who worked alone for the next 5 days, they can finish 5/12 of the job. How many days will each of them need to complete the job if they were to work alone?

Ahmad & Ben => 1 day =1/12 of job
Ahmad & Ben => 3 days = 1/4 of job
Ben alone => 5 days =( 5/12 - 1/4) = 1/6 of job
Ben alone = > 1 day = 1/30 of job
Ahmad alone => (1/12 - 1/30) = 1/20 of job
Ben will take 30 days & Ahmad will take 20 days if they work alone .

[tianzhu]

Hi

Hope this helps.

http://farm5.static.flickr.com/4053/4715375219_19cfa8eb65_b.jpg\">

Best wishes

[corneyAmber]

Vanilla Cake:

ksi:

Q12

-> In the figure, the shaded portion shows a 3m wide cemented walkway in a rectangular field of length 40cm and breadth 20m. Besides the walkway, rest of the rectangular field is covered with grass.
(a) Find the area of the walkway. (why is the answer 20m x 3m?)
(b) Find the area of the field that is covered with grass.

I cannot find the diagram on the net, can you furnish the diagram?

Hi ksi,
Here's the http://www.orlesson.org/orp/09Ma/2009-P6-Math-SA1-AiTong.pdf and pls go to page 19 for Q12 which is from Ai Tong 2009 P6 SA1 Paper 2 set on 14 May 2009.

Thanks VC.

Here's the explanation:
http://i724.photobucket.com/albums/ww246/ks2me/P6MathAiTongSA12009Q12-1.jpg\">

[Dharma]

ksi:

Vanilla Cake:

[quote=\"ksi\"]Q12

-> In the figure, the shaded portion shows a 3m wide cemented walkway in a rectangular field of length 40cm and breadth 20m. Besides the walkway, rest of the rectangular field is covered with grass.
(a) Find the area of the walkway. (why is the answer 20m x 3m?)
(b) Find the area of the field that is covered with grass.

I cannot find the diagram on the net, can you furnish the diagram?

Hi ksi,
Here's the http://www.orlesson.org/orp/09Ma/2009-P6-Math-SA1-AiTong.pdf and pls go to page 19 for Q12 which is from Ai Tong 2009 P6 SA1 Paper 2 set on 14 May 2009.

Thanks VC.

Here's the explanation:
http://i724.photobucket.com/albums/ww246/ks2me/P6MathAiTongSA12009Q12-1.jpg\">[/quote]Just imagine the drwg by ksi consist of 2 pieces of very huge tangrams on placed on field. These 2 pieces are separated by a gap of 3m wide walkway. If we slide one of the pieces of tangram so that the 2 pieces fit together, a gap will be left on the edge of the side of the tangram that has been slided in. This gap is the area of the walkway (3m x 20m = 60m2)

sorry for not being able to illustrate. If someone is able to draw it out it will be helpful. Thanks

[corneyAmber]

http://i724.photobucket.com/albums/ww246/ks2me/P6Aitong.jpg\">

[Dharma]

ksi:

http://i724.photobucket.com/albums/ww246/ks2me/P6Aitong.jpg\">

Thanks ksi for your clear illustration.