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LoginHelp pls... pri. 6 maths question i cant solve
20 posts
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i give tuition then end up these 2 questions i cant do at all. so can u help me pls guys?
btw, pls tell me how to solve without using algreba or equation since its supposed to be p6 work. thanks
q1 -
there r 60 shirts n pants in a store. each shirt cost $9 n pants $7. if the total cost of the shirts is $188 more than the total cost of the pants, how many shirts r there in the store?
q2 -
the number of grey marbles to black marbles is ratio 4:5. later, 8 grey marbles were taken out n 20 black marbles were added in. after that, the ration of grey to black marbles is 4:11.
how many marbles of each color were there in the end?
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Originally posted by the Bear:
these questions are designed to find the next Euler or Euclid in Singapore...
or to stress the hell out of children and parents who believe their children must be able to do these questions...
they definitely can do one
Just how long they take
Trial and error can solve a lot of pri sch questions de
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Originally posted by pongchak:
i give tuition then end up these 2 questions i cant do at all. so can u help me pls guys?
btw, pls tell me how to solve without using algreba or equation since its supposed to be p6 work. thanks
q1 -
there r 60 shirts n pants in a store. each shirt cost $9 n pants $7. if the total cost of the shirts is $188 more than the total cost of the pants, how many shirts r there in the store?
q2 -
the number of grey marbles to black marbles is ratio 4:5. later, 8 grey marbles were taken out n 20 black marbles were added in. after that, the ration of grey to black marbles is 4:11.
how many marbles of each color were there in the end?q2: maybe can use simulanteous equations
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Q2
Gray:Black = 4:5
Since 8 Grey marbles were taken out, the unsimplified ratio of Gray:Black must be more than or 2 times that of 4:5
Use Guess & Check.
12:15 becomes 4:35
16:20 becomes 8:40 = 1:5
20:25 becomes 12:45 = 4:15
24:30 becomes 16:50 = 8:25
28:35 becomes 20:55 = 4:11
So in the end, 20 Gray, 55 Black.
By algebra,
4x - 8 / 5x + 20 = 4/11
x=7
In the end
Gray: 4(7)-8 = 20
Black: 5(7) + 20 = 55
Edited by secretliker 17 May `08, 11:16PM
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also face the same problem with my sis. any other primary sch-accepted methods other than guess and check?
why do primary sch teachers not allow algebra to be use? the teachers minus marks from those using algebra, even though they got the correct answer.
also, when they progress to sec 1, they won't be allowed to use guess and check anymore wad, and have to use algebra to solve qsn. wouldn't it make more sense to allow them to use algebra?
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Originally posted by deathmaster:
why do primary sch teachers not allow algebra to be use? the teachers minus marks from those using algebra, even though they got the correct answer.
also, when they progress to sec 1, they won't be allowed to use guess and check anymore wad, and have to use algebra to solve qsn. wouldn't it make more sense to allow them to use algebra?
Unless the question specifically state don't use algebra. Otherwise, any correct method should be fine.
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This is a method using model. The easier way for students in Primary school to understand. I hope my reply is not too late. I really hope you would understand the model.
Firstly, since 8 is able to be divided by the 4 units, we wil do exactly that. Since the units are equal for both the grey and black marbles, we can also do the same for the units representing the black marbles.
Secondly, we will now look at the black marbles. since we can see that apart from the 5 original units, we still need 6 more units, since there are 11 units altogether in the end, we can draw 6 more unit, the size of (an original unit-2). Now, you must wonder where does this 6 units come from. Firstly, they come from the 20 marbles that are added in. But that is not all, there is also the 10 extra ones that we took out from the original unit. Thus, we can say that the 6 units is equals to 20+10. From there, i'm sure that you can work out the answer yourself.
My answer is: Blue-20marbles, Black-55 marbles.
I hope my answer is correct and i hope that it has helped you! This method can be used if any of the before and after ratio is the same; like this question.
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Originally posted by deathmaster:
also face the same problem with my sis. any other primary sch-accepted methods other than guess and check?
why do primary sch teachers not allow algebra to be use? the teachers minus marks from those using algebra, even though they got the correct answer.
also, when they progress to sec 1, they won't be allowed to use guess and check anymore wad, and have to use algebra to solve qsn. wouldn't it make more sense to allow them to use algebra?
Algebra can be used in pri sch; MOE said that it's perfectly fine and that marks would not be deducted in the PSLE. I used it in the PSLE without any problem. (:
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Originally posted by SBS 9613Z:
Algebra can be used in pri sch; MOE said that it's perfectly fine and that marks would not be deducted in the PSLE. I used it in the PSLE without any problem. (:
You are absolutely right.Problem with math is that when you go to secondary school, almost all you have learnt in primary school becomes useless. Primary school is about creative solving (when you get to P5-6 standard) and Secondary school is more focused on application of formulae etc.
Trust me you need to be able to do these to do well at PSLE. I still remember, I would scratch my head out for an entire day trying to solve a question if I had to. Do that, in the end you will benefit. Sometimes I fall asleep before I can solve it, but often that helps too because your mind is active when you are asleep. Then when I wake up BANG I know the answer.
Edited by MrSean 20 Jun `08, 4:43AM
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