Q&A - PSLE Math

[jesschan]

Deleted.

[Bunny27]

Suz855:

Total marks for 4 tests = 4q


Marks for the 4th test --> 4 q- 60-75-q =3q-135

Thank u

[PiggyLalala]

MathIzzzFun:

PiggyLalala:

[quote=\"MathIzzzFun\"]Here's the question. I put in 125% in red (only my guess).

http://i44.tinypic.com/1zr1jq9.jpg\">

Hi

http://www.flickr.com/photos/62167097@N02/6705370185/in/photostream

cheers.

Hi MathizzFun,
Can explain how do we know we have to let C to be 75 units?
Thank you very much

Hi

given Area A + Area B = 125% of Area C
so Area A + Area B : Area C = 5 : 4

We can use 5 units for area A + area B and 4 units for area C but we will need to deal with fractions/decimals. Since 1/5 of C was shaded, I decided on a multiple of 20 which is 60 units, but if one is comfortable dealing with decimals, then you can just set area C = 20 units.

cheers.[/quote] :thankyou: for yr prompt explanation

[MathIzzzFun]

PiggyLalala:

MathIzzzFun:

[quote=\"PiggyLalala\"]Here's the question. I put in 125% in red (only my guess).

http://i44.tinypic.com/1zr1jq9.jpg\">

Hi

http://www.flickr.com/photos/62167097@N02/6705370185/in/photostream

cheers.

Hi MathizzFun,
Can explain how do we know we have to let C to be 75 units?
Thank you very much

Hi

given Area A + Area B = 125% of Area C
so Area A + Area B : Area C = 5 : 4

We can use 5 units for area A + area B and 4 units for area C but we will need to deal with fractions/decimals. Since 1/5 of C was shaded, I decided on a multiple of 20 which is 60 units, but if one is comfortable dealing with decimals, then you can just set area C = 20 units.

cheers.

:thankyou: for yr prompt explanation[/quote] u r welcome

cheers.

[tianzhu]

pixiedust:

Thank you tianzhu, you saved my life ! Got them all...and will work hard to brush up my revision. Your help much appreciated !

Hi pixiedust

You’re welcome.

Best wishes

[tianzhu]

elkniwt:

Dear tianzhu,


Your illustration is always so clear and so beautiful. Thank you very much.

Hi elkniwt

You’re welcome.

Best wishes

[small]

Hi all,


Please help me on these number pattern questions as I always having problem to figure out the rule of them.

a) 1,5,22,112,,4720,

b) 8,22,64,190,,1702,5104,

c) 7,12,33,,189,___,1125.

Many thanks in advance.

[speedmaths.012624com]

small:

Hi all,


Please help me on these number pattern questions as I always having problem to figure out the rule of them.

a) 1,5,22,112,____,4720,______

b) 8,22,64,190,_____,1702,5104,______

c) 7,12,33,____,189,____,1125.

Many thanks in advance.

Hi,

a)
1 (x3 + 2) = 5
5 (x4 + 2) = 22
22 (x5 + 2) = 112
Can you continue from here?

b)
8 (x3 - 2) = 22
22 (x3 - 2) = 64
64 (x3 - 2) = 190
Can you continue from here?

c)
7 (x2 - 2) = 12
12 (x3 - 3) = 33
33 (x2 - 2) = 64
64 (x3 - 3) = 189
189 (x2 - 2) = ??
Can you continue from here?

Cheers



Speed Maths Centre
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=43&t=25433

[Fat Mama]

Hi,


Need help in this qn :

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

Tks

[MathIzzzFun]

Fat Mama:

Hi,


Need help in this qn :

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

Tks

Hi

IF 20 red ribbons added, Red: Blue = 2 units : 3 units
(At first, number of Red: Blue = 2 units - 20 : 3 units)

IF another 60 blue ribbons added,
Red : Blue
= 2 units : 3 units + 60
= 1 : 3

--> 2 units = 1 unit + 20 --> 1 unit = 20

Total number of ribbons = 5 units - 20 = 100 - 20 = 80

cheers.