Q&A - PSLE Math
-
Vanilla Cake:
Thanks VC.
Hi ksi,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?
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.
Here's the explanation:![](\"http://i724.photobucket.com/albums/ww246/ks2me/P6MathAiTongSA12009Q12-1.jpg\")
http://i724.photobucket.com/albums/ww246/ks2me/P6MathAiTongSA12009Q12-1.jpg\">
-
ksi:
Thanks VC.
Hi 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?
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.
Here's the explanation:
sorry for not being able to illustrate. If someone is able to draw it out it will be helpful. Thanks -
![](\"http://i724.photobucket.com/albums/ww246/ks2me/P6Aitong.jpg\")
-
ksi:
Thanks ksi for your clear illustration. -
Dharma:
No problem Dharma, just following your instructions. Good way to view it that way.
Thanks ksi for your clear illustration. -
My girl is preparing for PSLE and I am confused by the use of "If" in questions. Her teacher tells her one thing, her tuition centre another. And after speaking to a few teachers I know, there is clearly a lack of consistency.
For example:
I make up this question
There are Red and Blue marbles in the ratio 3 : 2. If 10 red marbles are lost, the ratio becomes 1:1. How many Red marbles are there at the end?
In this question, it seems logical that there is no real change to this question and we only use the 10 red marbles to find the answer. The answer would be found like this:
B4
R : B
3 : 2
After
R : B
2 : 2
1units ā> 10
There are 30 Red marbles at the end (and beginning) because no change has taken place.
Now what if the question is worded like this.
There are Red and Blue marbles in the ratio 3 : 2 at first. In the end, there is an equal number of Red and Blue marbles. If 10 Red marbles are removed, how many red marbles are there?
For this question, we should have 20 using the final ratio. Correct?
And finally
There are Red and Blue marbles in the ratio 3 : 5. The ratio of the number of Yellow marbles to Blue is 9:4.
a) bla bla bla
b) If 36 Yellow marbles are exchanged for Red and Blue, there would be the same amount of Red and Blue and there would be 50% more Yellow than Red. How many Blue marbles are there?
Before
R : B
3 : 5
12 : 20
Y : B
9 : 4
45 : 20
R : B : Y
12 : 20 : 45 (77 units)
After
R : B : Y
2 : 2 : 3 (7units)
22: 22 : 33 (77units)
How many blue marbles?
20 units ā> 20x36 = 720
Correct ?
What if the question is changed to this
a) bla bla
b) If 36 Yellow marbles are exchanged for Red and Blue, there would be the same amount of Red and Blue and there would be 50% more Yellow than Red, how many Blue marbles are there?
Given that the question "how many" is included in the sentence with the comma and not after a full stop, does this change the answer? This is where I get different answers. Some say because of the comma, the question wants an answer assuming it happened.
How to interpret this ?? -
Dear maths guru
Good morning.
Please help me on the following P6 maths:
1) Melvin, Thomas and Jack put some coins in a piggy bank. They wanted to donate some money to the charity, so Thomas and Jack took out 795 coins. Melvin and Thomas took out 5/13 of the coins from their piggy bank. Jack and Melvin took out 4/5 of the coins from their piggy bank. How many more coins did Thomas take than Melvin?
2) Ali had 5 meter of string. He used 1/4 meter of the string to tie 6 identical parcel. Find the length of the string left after tying 10 such parcels.
3) Find the sum of: 80+82+84+ā¦+158+160
Any short cut instead of writing all and adding them?
4) Mark collected some stamps and put them in two albums. The stamps in album A have a value of 50cents each while the stamps in album B have a value of 10cents each. The total value of stamps in album A was $77.60 more than stamps in Album B. He put 76 more stamps in Album B than in Album A. How much did Mark spend on the stamps in Album B?
Thank you
Firebird -
firebird:
I do the easiest one first as I need to scoot off...
3) Find the sum of: 80+82+84+....+158+160
Any short cut instead of writing all and adding them?
80+160 = 240
82+158 = 240
84+156 = 240
:
118+122=240
120
Number of pairs = (118-80)/2 + 1 = (160-122)/2 + 1 = 20
So total = 20*240 + 120 = 4920 -
To all the gurus,
I need clarification for the following question:
5/13 of a rectangular tank, 64 cm long, 30 cm wide and 65 cm high, was filled with water.
a) If 14.4 litre of water is poured into the tank, what would be the height of the water in the tank now?
b) Water is then poured into the tank at the rate of 480 cubic cm per minute. How long would it take for the tank to be completely filled? express your answer in h.
Do we take the height found in (a) to get the answer for (b) or do we treat (a) and (b) separately?
Thank you. -
liketoeat:
a)\tHeight of water in tank at first = 5/13 x 65cm = 25cmTo all the gurus,
I need clarification for the following question:
5/13 of a rectangular tank, 64 cm long, 30 cm wide and 65 cm high, was filled with water.
a) If 14.4 litre of water is poured into the tank, what would be the height of the water in the tank now?
b) Water is then poured into the tank at the rate of 480 cubic cm per minute. How long would it take for the tank to be completely filled? express your answer in h.
Do we take the height found in (a) to get the answer for (b) or do we treat (a) and (b) separately?
Thank you.
New height of water = > 14400cm3/(64cm x 30cm) + 25cm = 32.5cm
b)\tWater is then poured into the tank at the rate of 480 cubic cm per minute.
Need to find volume reqd to fill up tank =.( 64 x30 x 32.5)cm3 = 62,400cm3
Time => 62,400cm3/480cm3/min = 130 min = 2 1/6 hrs
Hello! It looks like you're interested in this conversation, but you don't have an account yet.
Getting fed up of having to scroll through the same posts each visit? When you register for an account, you'll always come back to exactly where you were before, and choose to be notified of new replies (either via email, or push notification). You'll also be able to save bookmarks and upvote posts to show your appreciation to other community members.
With your input, this post could be even better š
Register Login