Q&A - PSLE Math

[small]

lizawa:

tianzhu:

Maths Questions from http://www.channelnewsasia.com/discussion/forum.htm


3. A group of people met at a party. Each person shook hands with everyone else. Mr Li shook hands with 3 times as many men as women. Mrs Li shook hands with 4 times as many men as women. How many men and how many women were there at the party?

Answer : no. of men = 16; no. of women = 5

See working :

http://www.postimage.org/image.php?v=gx2w0utS

Hi lizawa,

I was not able to see the picture clearly, please can you send it to me or repost? thanks in advance.

Anyway I have to say thanks to all, great forum...help me a lots.

[ChiefKiasu]

small:

...I was not able to see the picture clearly, please can you send it to me or repost? thanks in advance...

Just click on the picture to enlarge.

[small]

Chef, I did but my browser did not show me the picture

[ChiefKiasu]

small:

Chef, I did but my browser did not show me the picture

Thanks, but the only thing I can cook is some mischief

You probably have some firewall or browser setting that is preventing pop-up windows. If you are using Microsoft IE, try right-clicking and select \"Open link in new tab\".

[corneyAmber]

ChiefKiasu:

small:

Chef, I did but my browser did not show me the picture

Thanks, but the only thing I can cook is some mischief

Off topic but this is so hilarious!! :lol:

[small]

Change to use firefox and it solved the problem.

[camomile]

Hi…can anyone help me with the following problem?


Uncle Sam paid $5250 for a plasma television. He paid the exact amount in $1oo and $50. He gave the cashier 90 notes in all. How many of them were $50 notes?

Ans: 75

I managed to solve it with the following ‘expression’:

100u + (90 x 50) - 50u = 5250
50u + 4500 = 5250
u = 750/50 = 15

therefore, no. of $50 = 90 - 15 = 75

Am trying to help coach my nephew as the parents can’t afford tuition (Dad was retrenched last year). But I don’t know how to explain to my nephew using the modeling method.

[Ruru]

Hi,my method is not the \"model\" method. It's based on assuming.


Let's say Uncle Sam gave the cashier 90 $100 notes. Then he would have given (90x$100) - $5250 = $3750 extra. If he were to exchange some of the $100 notes with $50 notes,how many he would need to exchange would be the answer to how many $50 notes there are.

For example,if he takes back $100 from the cashier and gives the cashier $50,the difference is $50. He has to divide $3750(the extra money) by the difference of $50 in order to find out how many $50 notes he needs to exchange.

Hence,$3750 divide by $50 = 75.

He has to take back 75 $100 notes and also give the cashier back 75 $50 notes. Since in the beginning we have already assumed that all the notes he gave were $100 notes,the exchanged 75 $50 notes is the answer. (He only exchange 75 notes,remember? So the rest were untouched.)

Hope u understand.

[camomile]

Hi Ruru....thanks for your help.


I managed to solve this problem using the assuming method too after having my dinner....Ha ha....can't work on on empty stomach.

If all notes are $50, 90 x $50 =$4500

remaining money (which are the halves of the $100) will be
5250 - 4500 = 750

750/50 = 15 (number of $100)

90 - 15 = 75 (ans)

Based it on one of the questions ( think its the legs of cows and chickens or something) in this thread. I'm so glad there's a forum like this for 'challenged' aunty like me

[lizawa]

small:

lizawa:

[quote=\"tianzhu\"]Maths Questions from http://www.channelnewsasia.com/discussion/forum.htm


3. A group of people met at a party. Each person shook hands with everyone else. Mr Li shook hands with 3 times as many men as women. Mrs Li shook hands with 4 times as many men as women. How many men and how many women were there at the party?

Answer : no. of men = 16; no. of women = 5

See working :

http://www.postimage.org/image.php?v=gx2w0utS

Hi lizawa,

I was not able to see the picture clearly, please can you send it to me or repost? thanks in advance.

Anyway I have to say thanks to all, great forum...help me a lots. :)[/quote]Hi small,

I just PM you. Give me your email address and I will email the solution to you.

lizawa