Q&A - PSLE Math

[MathIzzzFun]

lee tong fong:

Thanks MathIzzzFun for your contribution. I have 3 more questions that need your help in model or using simultaneous equation .


1)Leon bought some terrapins and guppies for a total of $96. He bought 3 times as many guppies than terrapins. He paid $30 more for the terrapins than for the guppies. Each terrapin cost $10.40 more than each guppy.
a)\tHow many terrapins did he buy?
b)\tWhat was the cost of each guppy?


2)Sally, Yiling and Ali shared a bag of beads. Sally received 3/4of the bag of beads and ¾ of the bead. Yiling received ¾ of the remaining bags of beads and ¾ of the bead. Ali received the last bead in the bag.
How many beads did Sally receive?

3) In the sack of 42 shirts and shorts, 40% of the shirts and 50% of the shorts were soiled. If 24 shirts and shorts were clean, how many soiled shirts and were there?

Thanks in advance

these have been discussed you may want to do a search with keywords to retrieve the previous posts...

1) http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=755281&hilit=guppies#p755281

2) http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=712005&hilit=Sally%2C+Yiling#p712005

3) T --> shirts, S --> shorts

total :
T T T T T } 42
........S S }

soiled :
T T } 42-24 =18
.. S }

clean:
T T T} 24
.....S}

T --> 24 - 18 = 6
S --> 18 - 2x6 = 6

soiled shirts --> 2 x 6 = 12

cheers.

[SAHMwith2boys]

Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

In the first place, dun understand the question.... :scratchhead:

[CoffeeCat]

SAHMwith2boys:

Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

In the first place, dun understand the question.... :scratchhead:

I think it means...
For every desk that exists in this fictional mathematical world, there is 4 stools surrounding it.
So there are 4 times as many stools as desks.


Just in case ....
so if number of desks is 1 unit, number of stools is 4 units.
Difference, 3 units = x
Total number of desks & stools = 5x/3

[SAHMwith2boys]

CoffeeCat:

SAHMwith2boys:

Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

In the first place, dun understand the question.... :scratchhead:

I think it means...
For every desk that exists in this fictional mathematical world, there is 4 stools surrounding it.
So there are 4 times as many stools as desks.


Just in case ....
so if number of desks is 1 unit, number of stools is 4 units.
Difference, 3 units = x
Total number of desks & stools = 5x/3

Answer provided was:

No. of desks : No. of stools = 1 : 4 = x : 4x
There are x desks.
There are 4x stools.

Anyone can help to decipher why the solution is this and what does the question wants?? :?

[Udon]

happyheart:

MathIzzzFun:

[quote=\"happyheart\"]Hi,

Need help to solve these using model please.

Q) Four children, Wilson, Felicia,Darren and Annabel sat for Math test and scored a total of 318 marks. Wilson and Darren scored the highest and the lowest respectively with a difference of 27 marks. The difference between Felicia's and Darren's score was 5 marks and the difference between Wilson's and Annabel's score was 13 marks. Find their individual scores.

Thank you!

You may want to draw the model ... I will represent Darren's block as 1 unit

Darren --> 1 unit
Wilson --> 1 unit + 27
Felicia --> 1 unit + 5
Annabel --> 1 unit + 14 (*= Wilson's score - 13)

So, 4 units (or 4 blocks in model) + 46 = 318
1 unit --> 68
...with this, the individual can then be worked out...

cheers.

MathIzzzfun...you make both questions look so simple. Thank you![/quote]
Hi Happyheart...

You are now preparing for 2013 PSLE?

[tianzhu]

SAHMwith2boys:

Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

Hi

Hope this helps.

Best wishes.

http://farm9.staticflickr.com/8083/8343943343_1d944d95e8_z.jpg\">

[CoffeeCat]

SAHMwith2boys:

CoffeeCat:

[quote=\"SAHMwith2boys\"]Hi, need help in this Maths question:


Every desk has 4 stools surrounding it. How many desks and stools are there if there are x more stools than desks?

In the first place, dun understand the question.... :scratchhead:

I think it means...
For every desk that exists in this fictional mathematical world, there is 4 stools surrounding it.
So there are 4 times as many stools as desks.


Just in case ....
so if number of desks is 1 unit, number of stools is 4 units.
Difference, 3 units = x
Total number of desks & stools = 5x/3

Answer provided was:

No. of desks : No. of stools = 1 : 4 = x : 4x
There are x desks.
There are 4x stools.

Anyone can help to decipher why the solution is this and what does the question wants?? :?[/quote]hmm I misread the question as \"total number of desks and stools\".
Anyway maybe there was a typo in the question. They meant to say there are x desks and not x more stools than desks.

[Dad8282]

Hi,


Need help with the following questions:

1. I have some red and blue ribbons in a bottle.
If I add in 20 red ribbons, 60% of my ribbons are blue.
If I add in another 60 blue ribbons, 75% of my ribbons are blue.
How many ribbons have I in the bottle?

2. Rectangle A overlaps with Rectangle B. Rectangle A is twice the size of Rectangle B.
If 1/3 of Rectangle B overlaps with Rectangle A, what fraction of Rectangle A
overlaps with Rectangle B?

Thanks.

[tianzhu]

Hi


Q1 has been discussed in our earlier posts.

You may wish to refer to them.

http://www.kiasuparents.com/kiasu/forum/viewtopic.php&f=69&t=280&p=712514

Best wishes

[tianzhu]

Dad8282:

2. Rectangle A overlaps with Rectangle B. Rectangle A is twice the size of Rectangle B.
If 1/3 of Rectangle B overlaps with Rectangle A, what fraction of Rectangle A
overlaps with Rectangle B?

Thanks.

Hi

A neat way is to use MD or draw two boxes of different sizes and labeling them with units.

Draw 6 boxes to show the size of rectangle A. Use 5 boxes to show its unshaded portion and 1 box to show the shaded portion.

Draw 3 boxes to show the size of rectangle B. Use 2 boxes to show unshaded area, the shaded portion is the same as rectangle A.

Hence, fraction of A overlapping B ------ 1/6

Best wishes