Q&A - P3 Math

[Devnahouse]

Sorry. I interpret the question wrongly.


This shld be a "Work Backward" method. \t\t\t\t\t\t\t
3 of them have equal share of 21, must be 7 marble each for Alfred, Ben and Chuck.\t\t\t\t\t\t\t
\t\t\t\t\t\t
1) Add back what they have at first:\t\t\t
2) Then minus off what they receive from each other

Alfred
7 + 2(gives to Ben) - 1 (receives from Chuck) = 8

Ben :
7 + 3 (gives to Chuck) - 2 (receives from Alfred) = 8

Chuck :
7 + 1 (gives to Alfred) - 3 (receives from Ben) = 5
\t\t\t\t

\t
Now check again,\t\t\t\t\t\t\t
Alfred has 8 at first, gives away 2 to Ben and receives 1 from Chuck = 7
Ben has 8 at first, gives away 3 to Chuck, and receives 2 from Alfred, = 7
Chuck has 5 at first, receives 3 from Ben, and gives away 1 to Alfred = 7

Hope is correct now.

[Dharma]

elkniwt:

Hi,


I was going thr' this paper with my P3 girl. Need help in this qn. Thanks

Catholic High 2007 CA2 Q40.

http://www.postimage.org/image.php?v=Ts2ds4FJ

Hi elkniwt,

You have 5 boxes, (top, bottom, left, right and middle)

The unknown is the middle one in the 3rd diagram. For patterns you need to find the relationship of the numbers of 4 outer boxes and the number in the middle box. You need to manipulate the numbers using the 4 basic operations and see if you get the number in the middle box for the 1st and 2nd diagrams. If they are correct, then you have established the pattern and go get the middle number in the 3rd diagram.

1st diagram
Left box + Top box = 1/8 + ¾ = 7/8
Right box + Bottom box = 3/8 + 1/8 = 4/8
Middle box = 7/8 – 4/8 = 3/8

2nd diagram
Left box + Top box = 1/3 + 1/6 = 4/12 + 2/12 = 6/12
Right box + Bottom box = 4/12 + 1/12 = 5/12
Middle box = 6/12 – 5/12 = 1/12

3rd diagram
Left box + Top box = 1/3 + 1/3 = 3/9 + 3/9 = 6/9
Right box + Bottom box = 3/9 + 1/9 = 4/9
Middle box = 6/9 – 4/9 = 2/9

[Dharma]

Daddy:

//Moderator's note: Topics merged.


Hi,

I have one difficult question to ask. Please help. Thank.

\"Alfred, Ben and Chuck have some marbles. They have 21 marbles altogether. If Alfred gives Ben 2 marbles. Ben gives Chuck 3 marbles and Chuck gives Alfred 1 marbles, they will have equal numbers of marbles each. How many marbles does each of them have at first?\" :?

Thanks
daddy

http://www.postimage.org/

[Tang]

"Alfred, Ben and Chuck have some marbles. They have 21 marbles altogether. If Alfred gives Ben 2 marbles. Ben gives Chuck 3 marbles and Chuck gives Alfred 1 marbles, they will have equal numbers of marbles each. How many marbles does each of them have at first?"


21 / 3 = 7

Alfred – 7 - 1 + 2 = 8 marbles

Ben – 7 + 3 - 2 = 8 marbles

Chuck – 7 + 1 - 3 = 5 marbles


Suggested solution by Tang’s sister

[Tang]

"Gregory and Timothy has 192 stickers together. After Timothy gave 30 stickers to Gregory, Timothy had thrice as many sticker as Gregory. How many stickers did Gregory have at first?"


4u – 192
1u – 192 / 4 = 48

G – 48 - 30 = 18 stickers

[Daddy]

Thanks Devnahouse. I understood and going to teach my duaghter.

[Suz855]

//Moderator's note: Topics merged


Hi,

Not sure this qn should even be classify under P3 maths, anyway looking for a simplify soln, do share if you have good suggestion. No algebra or simultaneous equation, thanks

Qn :
There were 84 apples and pears in a box at first. When 2/5 of the apples
and 2/3 of the pears were eaten, there were 40 fruits left.

a) How many apples were there at first
b) What fraction of the fruits left were pears?

[tutormum]

Just take the extra 2 balloons and add the 2 more she needs. That will be 4. If she gives 6 each at first, and 8 each later, that means she gives each student another 2 each. Since she have 4 balloons to give away, she has 2 students.

Check: If she gives 2 students 6 balloons, she’ll have given 12, 2 X 6 = 12, there is 2 extra, therefore she has 14 balloons at first.
If she gives 2 students 8 balloons, she’ll have to give 2 X 8 = 16. As she has only 14 balloons, she needs 2 more.
Let me give another example.
If Ken gives each child 10 sweets, he’ll have 3 left. If he gives each child 1 more, he needs another 5 sweets. How many children are there?
Just take 3 + 5 = 8. If he gives each 1 more, he’ll give away all 8 sweets, right? So there are 8 children.
Check: 8 X 10 = 80 + 3 = 83 sweets in total
If he gives 1 more each, he needs 5 more, that is he needs 83 + 5 = 88. Since 1 child will be given 11, which is originally 10 + 1 more. 88/11 = 8.
For this type of question, just add the extra and the required number and work from there.
Hope my explanation is clear.

[tutormum]

Ooops. Sorry, forgot to quote. My early reply is for the following question.


A teacher gave her students some balloons. If she gave 6 balloons to each student, she will have 2 balloons left. If she gave 8 balloons to each student, she will be short of 2 balloons. What is the smallest possible number of students she has?

Try to do this without using ALGEBRA!

[tutormum]

Suz855:

//Moderator's note: Topics merged


Hi,

Not sure this qn should even be classify under P3 maths, anyway looking for a simplify soln, do share if you have good suggestion. No algebra or simultaneous equation, thanks

Qn :
There were 84 apples and pears in a box at first. When 2/5 of the apples
and 2/3 of the pears were eaten, there were 40 fruits left.

a) How many apples were there at first
b) What fraction of the fruits left were pears?

Take 2 unit of apples + 2 unit of pears = 44 fruit eaten (84 - 40 = 44). Therefore 1 unit of apples + 1 unit of pears = 22 (44/2 sets)
Left 3 units of apples and 1 unit of pears = 40
As 1 unit of apples and 1 unit of pears = 22, 2 units of apples will be 40 - 22 = 18. Therefore 1 unit of apples = 18/2 = 9
Therefore, there are 9 X 5 units = 45 apples at first.
1 unit of pears will be 22 - 9 = 13. There are 13 X 3 = 39 pears at first.
Therefore fraction of fruits left were pears = 13/40.