BeContented:

ksi:

cwc, hv u offered the reasoning?


Intuitively my answer was 'black' last night but I was too tired to write my reasoning. Now that you have confirmed black is correct, let me share my thoughts.

The 2 non-blind men saw 1 black and 1 white hat.
Hence, to guess their own colour, it could be a white probability is 1/3 and black is 2/3.

Now if man 1 saw
white on blind man and
black on man 2,
then man 2 should see white on blind man and black on man 1, and remaining hats should be 1 white and 1 black.

And if man 1 saw black on blind man
and white on man 2
then man 2 should see black on blind man and white on man 1, and remaining hats should be 1 white and 2 blacks.

Hence the [b]blind man should be wearing black hat[/b] since man 1 and man 2 cannot tell what colour they are wearing.

cwc, tio bo?

Xiao lao.....I also dunno right or wrong....I need to check back with higher order teacher (hubby lah....) but my reasoning is as follows :

Man1
--> Either he sees 2B or 1W1B....and M1 can be either color. That's why does not know his own color.

Man2
--> IF Blind is W, M2 can only be B based on above.....but since M2 cannot guess his own hat color, Blind man is NOT W.

So we have established Blind is Black hat.
Regardless of M1 hat color, M2 can be B or W.....that's why he does not know his own color too.

Based on answer by Man1 & 2, Blind can only be Black...hence he knows.

Am I confusing you??

alng:

Hi,


Since we are on this topic of mummies teaching maths, I thought I would share my recent thoughts and actions in teaching maths to my P5 girl. She has been good in maths from P1 to P4 with an average score of above 95% until P5 SA1. I usually leave her alone to do her maths unless she has questions to ask me. I will help her to revise for exam too.

I find P5 maths very tough and no where near what we have studied previously. It is not just the solving of maths using non-algebra method. In 2011, whenever my girl asked me questions on maths, I had to spend hours to figure out first before teaching her. Of course there were questions I could not figure too and I asked her to forget about it :-). This has affected her SA1 maths results. For once, she scored below 90%. But it was still a good result.

The agony lasted till mid Sep 2011 when I attended the Maths workshop conducted by 90.5 FM. There was only one thing I learnt from that near 4-hour workshop on Sunday afternoon. That is MOE is not teaching maths as maths per se. MOE is using maths as a platform to teach problem solving skills. This explains why the maths problems are so difficult now. With this understanding, I change my teaching method even though we were less than three weeks to SA2. When my daughter cannot do a maths question, I no longer spend the hours trying to solve the question first before teaching her. I sit down with her to figure out the question together. I ask logical questions and we both try to draw the model or use other methods to solve the question. Very often, she figures it out half way through our discussion and solve the question on her own. Once she figures out, I will stop thinking and let her continues on her own. This has reduced much agony on my side. My daughter feels so much more confident in attempting maths questions. We even went through those questions that defeated us at SA1 and we could solve them now. Basically, we treat the maths questions as problems and use logical thinking and ways to solve it. My daughter no longer needs to memorize some steps when she could not understand the problems and solutions.

The results have been very positive. Besides her increased confidence, she feels great after the maths exam on Friday. She said that paper 2 questions were all do-able. Whenever she says that, we can look forward to near full marks unless she made careless mistakes.

ksi:

Hey why lose job? My job is only a mummy. I don't teach my child at all leh....she learns on her own from her teachers. So mummy job is forever as far as I know. I solve math and science questions for fun only, just so I understand what my kid is doing and facing in school. Also, since your kids can solve the problem, you really can sit back and relax.

JRLam:

[quote=\"ksi]


You mean you want the answer to this question instead of the corrected question where the answer is
$1- 1190
$0.50 - 712
$0.20 - 660?
Let me know which one then I write the solutions for you.

JRLam:

ksi:

[quote=\"BeContented\"]A piggy bank has a total of 2562 coins consisting of one-dollar coins, fifty-cent and twenty-cent coins. 3/7 of the one-dollar coins and 32 of the fifty-cent coins are put in. After that, there is an equal number of one-dollar, fifty-cent, twenty-cent coins in the piggy bank. How many of each type of coins are there in the piggy bank at first?



Jia lak......my 2 kids (P4 & P5) managed to come out with a solution within 5 mins.......while I am still stuck after 10mins and had to refer to their solutions. The mommy need to go tuition liao.....

My solution in 2 mins, tio bio?

At first,
$1 - 488
$0.50 - 822
$0.20 - 854

I just realised I solved the other problem in April so that was an Apr ksi....now the Oct ksi is quite jaded..... :rotflmao:

BeContented:

ksi:

[quote=\"BeContented\"]Ksi, sorri sorry. Realised I missed out a line.....after checking your answer. Can try again?

$1 - 1190
$0.50 - 712
$0.20 - 660

tio bo?

ksi:

BeContented:

A piggy bank has a total of 2562 coins consisting of one-dollar coins, fifty-cent and twenty-cent coins. 3/7 of the one-dollar coins and 32 of the fifty-cent coins are put in. After that, there is an equal number of one-dollar, fifty-cent, twenty-cent coins in the piggy bank. How many of each type of coins are there in the piggy bank at first?



Jia lak......my 2 kids (P4 & P5) managed to come out with a solution within 5 mins.......while I am still stuck after 10mins and had to refer to their solutions. The mommy need to go tuition liao.....

My solution in 2 mins, tio bio?

At first,
$1 - 488
$0.50 - 822
$0.20 - 854

I just realised I solved the other problem in April so that was an Apr ksi....now the Oct ksi is quite jaded..... :rotflmao:

ksi:

BeContented:

Ksi, sorri sorry. Realised I missed out a line.....after checking your answer. Can try again?

$1 - 1190
$0.50 - 712
$0.20 - 660

tio bo?

BeContented:

Ksi, sorri sorry. Realised I missed out a line.....after checking your answer. Can try again?

BeContented:

A piggy bank has a total of 2562 coins consisting of one-dollar coins, fifty-cent and twenty-cent coins. 3/7 of the one-dollar coins and 32 of the fifty-cent coins are put in. After that, there is an equal number of one-dollar, fifty-cent, twenty-cent coins in the piggy bank. How many of each type of coins are there in the piggy bank at first?



Jia lak......my 2 kids (P4 & P5) managed to come out with a solution within 5 mins.......while I am still stuck after 10mins and had to refer to their solutions. The mommy need to go tuition liao.....

ksi:

cwc, hv u offered the reasoning?


Intuitively my answer was 'black' last night but I was too tired to write my reasoning. Now that you have confirmed black is correct, let me share my thoughts.

The 2 non-blind men saw 1 black and 1 white hat.
Hence, to guess their own colour, it could be a white probability is 1/3 and black is 2/3.

Now if man 1 saw
white on blind man and
black on man 2,
then man 2 should see white on blind man and black on man 1, and remaining hats should be 1 white and 1 black.

And if man 1 saw black on blind man
and white on man 2
then man 2 should see black on blind man and white on man 1, and remaining hats should be 1 white and 2 blacks.

Hence the [b]blind man should be wearing black hat[/b] since man 1 and man 2 cannot tell what colour they are wearing.

cwc, tio bo?

tisha:

cwc:

[quote=\"tisha\"]
The blind man is wearing a black hat the other two are weraing a white hat.

Yes, the blind man is definitely wearing a black hat.
But the other two may not be wearing white

cwc:

tisha:

[quote=\"cwc\"]Another question....not Maths, more logical reasoning.


There are 3 men and 1 is blind. There are 3 black hats and 2 white hats in a basket. Each of them will just pick up a hat and put on his head without knowing the color.

The first man looked at the 2nd man and the blind, he thinks for a while and says \"I dun know the color of my hat\".
The 2nd man looked at the 1st man and the blind, he thinks for a while and also says \"I dun know the color of my hat too\".
The blind man says \"I know the color of my hat\".
How?

Have fun

The blind man is wearing a black hat the other two are weraing a white hat.

tisha:

cwc:

Another question....not Maths, more logical reasoning.


There are 3 men and 1 is blind. There are 3 black hats and 2 white hats in a basket. Each of them will just pick up a hat and put on his head without knowing the color.

The first man looked at the 2nd man and the blind, he thinks for a while and says \"I dun know the color of my hat\".
The 2nd man looked at the 1st man and the blind, he thinks for a while and also says \"I dun know the color of my hat too\".
The blind man says \"I know the color of my hat\".
How?

Have fun

The blind man is wearing a black hat the other two are weraing a white hat.

cwc:

Another question....not Maths, more logical reasoning.


There are 3 men and 1 is blind. There are 3 black hats and 2 white hats in a basket. Each of them will just pick up a hat and put on his head without knowing the color.

The first man looked at the 2nd man and the blind, he thinks for a while and says \"I dun know the color of my hat\".
The 2nd man looked at the 1st man and the blind, he thinks for a while and also says \"I dun know the color of my hat too\".
The blind man says \"I know the color of my hat\".
How?

Have fun

cwc:

It's upper primary level ~P4&5......
I'm also rusty .... seeing how slow I am compared to my DS, I went to dig out the uncompleted P4 & P5 maths assessment book to try. Intend to DRILL myself to see if can catch up in 3 months' time. But as I do, I realised how tedious it is for the poor children, being DRILL daily....5 sums only I start to feel tired :oops:

AND I thot I was pretty good in MATHS.....now having 2nd thots.....

pixiedust:

Tap A&B

I got ans:7.5 mins also but I took 4 mins and with a calculator to help me ! :stupid:

B&W Hats
I tried to draw probability table until my eyes crossed. 10 mins already...cannot solve !