Q&A - P3 Math

[watmekiasu]

I've deleted my answer since it is not right. Do not wish anyone to waste time figuring out my method. :lol:

[elkniwt]

watmekiasu:

Elkniwt


Hope this is correct -

1st - 3/8 + 3/8 = 6/8 = 3/4
2nd - 1/12 + 1/12 = 2/12 = 1/6
3rd - 1/3 + 1/6 = 3/6 = 1/3

so, the answer is 1/6

The ans given by the ans sheet is 2/9. I couldn't get it.

[qic]

The answer is as follows:


3/8-1/8+3/8/+1/8=6/8=3/4
4/12-1/3+1/12+1/12=2/12=1/6
3/9-1/3+?+1/9=1/3=3/9

?=2/9

[elkniwt]

qic:

The answer is as follows:


3/8-1/8+3/8/+1/8=6/8=3/4
4/12-1/3+1/12+1/12=2/12=1/6
3/9-1/3+?+1/9=1/3=3/9

?=2/9

Wow!! thanks!!! The pattern is quite unusual. Not easy to see the pattern even after I know the ans. Wondering how am I going to teach my dd to attempt it ?? Thanks again.

[Devnahouse]

Can help...... pls.. :?


Anglo Chinese P3 SA2 2007:
Mother has some money to buy beef. She will have $15 left if she buys 3kg of beef. However, she will need $3 more if she wants to buy 4kg of beef instead. How much money does Mother have?

Answer is $69? How?

[corneyAmber]

The model diagram is like this:


xxx+15 = amount of money mother has (where x= cost of 1 kg of beef)

xxxx - 3 = amount of money mother has

3 units +15 = 4 units - 3
Hence 1 unit = 18

So amt mother has = ( 3*18 ) + 15 = $69

[Devnahouse]

Hi Ks2me,

Ok, understand now if 3x + 15 = 4x -3. Thanks. But… how to explain this
simultaneous equation to P3 kid at their level?

[tianzhu]

Hi, hope this helps.


http://farm4.static.flickr.com/3463/3993421153_4806021a53_o.jpg\">

[Devnahouse]

Hi Tianzhu,

Thank you. Explaination on a fresh beef in the background.
I'm a visual person. The bars and the beef instantly make a difference.

:stupid: I din know how to explain $15 + $3 at first but now understand it is due to the difference of 1 kg, thus 1 kg = $18 and 3 * $18 + $15 is the initial money that mother has.

:idea:

[acforfamily]

bwpj2000:

Q1. Edward has $40 more than Fariq. If Edward gives 1/5 of his money to Fariq, Fariq will have 7/8 as much money as Edward. How much money do they have altogether?

I have done it using model method, but don't know how to paste the image :oops:
so I hope this helps.

After giving away 1/5, Edward has 8 units while Fariq has 7
Edward has 4/5 of his original, so 8 units = 4/5 of original;
before giving away, Edward would have 10 units
difference of 2 units
then Fariq would have only 5 units (7=2)
Difference between the 2 is 5 units which is = $40
1 unit = 40/5 = 8
therefore total would be 15 units * $8 = $120