Does anyone have few questions on using assumption method? need my girl to try. TIA.
Replies
32
Zhong Shu Hao
120 students weigh an average of 60kg.
each boy weighs 63kg.
each girl weighs 59kg.
whats the difference.
between the number of boys and the number of girls?
6 years ago
Wahidah Khan
thk u
6 years ago
Serene Khoo
Can show ans?
6 years ago
Raymond Ng
6 years ago
Mayuree Thongpan
6 years ago
Raymond Ng
Here's the answer. Similar working. Try it โบ
6 years ago
Wahidah Khan
thk u all.
6 years ago
Mayuree Thongpan
There are many levels of the questions that can use assumption to solve, we may choose the appropriate one depends on the student's level.
One of the difficult question is here.. I think๐, my method may not a good one but the question is challenge Let's try.
6 years ago
Wahidah Khan
i guess for this one i would rather go for guess n check. wht u think
6 years ago
Wahidah Khan
coz there are 3 numbers here $5 $10 and $50
6 years ago
Raymond Ng
6 years ago
Wahidah Khan
yup guess n check
6 years ago
Wahidah Khan
thk u everyone
6 years ago
Wahidah Khan
just a qsn in assumption method does it matter if we assume a lower fig thn the larger one? for eg $2 and $5... we assume all $2 or assume all $5
6 years ago
Zhong Shu Hao
Does not matter. Both will get you the same answer.
6 years ago
Wahidah Khan
thk u
6 years ago
Zhong Shu Hao
But if the question ask for no of $2..... Start off by assuming all $5.
6 years ago
Wahidah Khan
yes tts the one
6 years ago
Zhong Shu Hao
ie,
If the Q ask for "A", assume all are "B".
Will save you some steps.
6 years ago
Zhong Shu Hao
But even if you all are "A"... You will get the same ans, just that u use more steps (and time).
6 years ago
Raymond Ng
Straight As... sounds good ๐
6 years ago
Zhong Shu Hao
.... maybe I should use X and Y instead....
6 years ago
Wahidah Khan
ok so if qsn ask A assume all B if qsn ask B assume all A. thk you so much one and all
6 years ago
Zhong Shu Hao
Yup
6 years ago
Rye Tan
Wahidah Khan, This is a Question which my friend (alr in this thread....) and I came up with. Invovles the use f assumption method, but brings it to a slightly higher level probably?
Taken from our Mock Paper
6 years ago
Wahidah Khan
thk u
6 years ago
Mayuree Thongpan
6 years ago
Rye Tan
Here are the solutions to the question.
6 years ago
Rye Tan
6 years ago
Wahidah Khan
how u solve it Rye
6 years ago
Wahidah Khan
wow tough
6 years ago
Raymond Ng
6 years ago
Raymond Ng
Straight As... sounds good ๐
6 years ago
Zhong Shu Hao
.... maybe I should use X and Y instead....
6 years ago
Adrian Ng
Asked 9 years ago
SG
chevron_right
Primary 3
chevron_right
Number and Algebra
Making it visual...
Replies
0
Loo Jane
Asked 9 years ago
SG
chevron_right
Primary 3
chevron_right
Number and Algebra
Please help. How do I solve this P3 problem sum? Trial n error?
Replies
24
Caryn Mok
Week 1 $10.
Week 2 $10 + 4
Week 3 10+(4x2) note that we always multiply 4 with a number that is minus 1 from the week.
Week 4 10 + (4x3)
...
So 154-10=144.
144รท4=36
36+1=37
So it takes 37weeks.
To check:
Week 37 10+(4ร36)=10+144 =154.
Hope this is correct..:)
6 years ago
Izam Marwasi
6 years ago
Loo Jane
Thank you for the suggested answers.
Using Trial & error method, i add week 1-7 savings,
10+14+18+22+26+30+34=$154
Is there a formula or shorter method to solve?
6 years ago
Caryn Mok
Oops.. seems like my answer is wrong! Didn't take into account that that it's cumulative.
6 years ago
Ariel Lim Ah Ping
This is number pattern. Once u are familiar with this pattern, +4, +4, +4,
Just find what number +4. In this case,
10 = 6 + 4
So the formulae is 6 +4n,
Where n = number of weeks
6 years ago
Raymond Ng
6 years ago
Izam Marwasi
Raymond Ng. What's wrong with my working?? Thanks
6 years ago
Raymond Ng
Izam Marwasi, your answer would have been perfectly fine if the question is
"In which week would she have saved $154"
But now, the question is apparently asking how many weeks have passed before her piggybank has accumulated $154.
Hope that helps โบ
6 years ago
Izam Marwasi
Thanks..
6 years ago
Raymond Ng
In any case, if you want to calculate in which week she would save $154, an alternative method is
(154 - 6) รท 4 = 37
6 years ago
Loo Jane
Thank you Raymond.
Its a P3 qn. Kids yer to learn algebra.
6 years ago
Raymond Ng
2 ร 7 ร 11 isn't algebra โบ
I merely used n coz someone asked if there is a formula. Think of it this way:
The accumulated amount saved are: 10, 24, 42, ...
10 = 2 ร 1 ร 5
24 = 2 ร 2 ร 6
42 = 2 ร 3 ร 7
...
See the pattern?
6 years ago
Loo Jane
Thank you Raymond.
I was told the only way is to keep adding till I get $154 for P3 lvl. Sch won't gv them a big figure to work with.
6 years ago
Raymond Ng
Sure. Keep adding is fine so long as the number isn't too big e.g. 960 โบ
6 years ago
Loo Jane
๐ฐ๐ฐ๐ฐ๐ฐ
6 years ago
Raymond Ng
Be it P3/4/5/6 or Sec1/2/3/4/5 or JC1/2,
When it comes to number patterns, my advice to students is the same: get the general nth term, then you can get ANY term โบ
6 years ago
Kwang Huang Sim
Another method which I like to use. Since it's an increase of 4 throughout.
Wk 1 - 1 X 4 + 6 = 10
Wk 2 - 2 X 4 + 6 = 14
Wk 3 - 3 X 4 + 6 = 18
So 154 = __ X 4 + 6
6 years ago
Ariel Lim Ah Ping
p3 Parents, do join us at https://www.facebook.com/groups/therealparents2006/
You may be required to verify that u are a real parent.
6 years ago
Chong Ji Lian
Raymond ng is correct. The question wants accumulated total. If you just add $4 that is just that amount saved for that week. Not inclusive of the amounts of the previous week.
Oops.. seems like my answer is wrong! Didn't take into account that that it's cumulative.
6 years ago
Raymond Ng
Izam Marwasi, your answer would have been perfectly fine if the question is
"In which week would she have saved $154"
But now, the question is apparently asking how many weeks have passed before her piggybank has accumulated $154.
Hope that helps โบ
6 years ago
Izam Marwasi
Thanks..
6 years ago
Raymond Ng
2 ร 7 ร 11 isn't algebra โบ
I merely used n coz someone asked if there is a formula. Think of it this way:
The accumulated amount saved are: 10, 24, 42, ...
10 = 2 ร 1 ร 5
24 = 2 ร 2 ร 6
42 = 2 ร 3 ร 7
...
See the pattern?
6 years ago
Raymond Ng
In any case, if you want to calculate in which week she would save $154, an alternative method is
(154 - 6) รท 4 = 37
6 years ago
Loo Jane
Thank you Raymond.
I was told the only way is to keep adding till I get $154 for P3 lvl. Sch won't gv them a big figure to work with.
6 years ago
Raymond Ng
Sure. Keep adding is fine so long as the number isn't too big e.g. 960 โบ
6 years ago
Loo Jane
๐ฐ๐ฐ๐ฐ๐ฐ
6 years ago
Raymond Ng
Be it P3/4/5/6 or Sec1/2/3/4/5 or JC1/2,
When it comes to number patterns, my advice to students is the same: get the general nth term, then you can get ANY term โบ