Q&A - PSLE Math

[shurley197323]

Thanks. Tianzhu

[hypergatak]

hi


Appreciate your input to the following question:-
1/1x2 + 1/2x3 +1/3x4 +…1/2009x2010 +1/2010x2011.

[lizawa]

hypergatak:

hi


Appreciate your input to the following question:-
1/1x2 + 1/2x3 +1/3x4 +...........................................1/2009x2010 +1/2010x2011.

You need to see the pattern that
1/1x2 = 1/1 - 1/2
1/2x3 = 1/2 - 1/3
1/3x4 = 1/3 - 1/4 etc

So expand the question, you get
1/1 - 1/2 + 1/2 -1/3+1/3 -1/4.......+ 1/2010 - 1/2011
All terms in the centre are eliminated except first and last
= 1/1 - 1/2011 = 2010/2011

[hypergatak]

Thanks for your help.

[speedmaths.012624com]

hypergatak:

hi


Appreciate your input to the following question:-
1/1x2 + 1/2x3 +1/3x4 +...........................................1/2009x2010 +1/2010x2011.

P6 pupils (2012) can learn to answer such questions in our PSLE Maths camps.

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


Speedmaths.com

[Chan09]

Some help on this:

Mr Tan saves 15% of his salary. His savings increased by $18 when his salary increases by 5%. what is his salary before the increase?
Ans:$2400

[lizawa]

Chan09:

Some help on this:

Mr Tan saves 15% of his salary. His savings increased by $18 when his salary increases by 5%. what is his salary before the increase?
Ans:$2400

Before :
Savings : 15%; salary : 100%
After :
Salary : 105%
savings -> 15% x 105 = 15.75%
0.75% -> 18
(salary before increase) 100% -> 18/0.75 x 100 = 2400

[JadeDry]

Hello,


I would appreciate input on this question:

Simplify:

((3 X squared-Y cubed) / (8 Z-squared)) / ((9 Y-squared)/10Z)) x ((6 Y-squared- Z cubed) / 5X))

My answer is ((X-Y cubed- Z squared) /2 ) Is this correct?

Thanks in advance for your assistance.

[sleepyqueen]

JadeDry:

Hello,


I would appreciate input on this question:

Simplify:

((3 X squared-Y cubed) / (8 Z-squared)) / ((9 Y-squared)/10Z)) x ((6 Y-squared- Z cubed) / 5X))

My answer is ((X-Y cubed- Z squared) /2 ) Is this correct?

Thanks in advance for your assistance.

Yes this is what I get also, hope we are right.
answer: (xy3z2)/2

[linden2000]

Hi. For the Nanyang Pri School’s P6 CA1 paper 2 question 18 (last question of paper 2), does anyone have any idea what is the missing number in the following sentence?


"The total area of Triangle A and Triangle B is _______of the area of Triangle C."

Other than algebra, how would we solve this question?

Many thanks.