Q&A - PSLE Math

[SAHMwith2boys]

Can someone help with the below question:

http://i46.tinypic.com/14qyd3.jpg\">

It's taken from 2012 CHIJ CA1 paper.

[MathIzzzFun]

SAHMwith2boys:

Can someone help with the below question:

http://i46.tinypic.com/14qyd3.jpg\">

It's taken from 2012 CHIJ CA1 paper.

http://i48.tinypic.com/hvqj42.png\">

cheers.

[SAHMwith2boys]

MathIzzzFun:

SAHMwith2boys:

Can someone help with the below question:

http://i46.tinypic.com/14qyd3.jpg\">

It's taken from 2012 CHIJ CA1 paper.

http://i48.tinypic.com/hvqj42.png\">

cheers.

This method seems a bit tough for Primary level, was wondering is there any other way to do this?

[MathIzzzFun]

SAHMwith2boys:

MathIzzzFun:

[quote=\"SAHMwith2boys\"]Can someone help with the below question:

http://i46.tinypic.com/14qyd3.jpg\">

It's taken from 2012 CHIJ CA1 paper.

http://i48.tinypic.com/hvqj42.png\">

cheers.

This method seems a bit tough for Primary level, was wondering is there any other way to do this? [/quote]The solution is not beyond P6 students.

2 key information are provided - triangle ABC is isosceles and angle AGE = 75 deg. So, one has to made use of these to work out the solution.

another approach is to work out the angle CAG in terms of the angles EFC and FCA and then use the interior angles of quadrilateral ACFG to work out angle FCA (1u)

angle CAG = 180 -(90-1u) = 1u + 90
in quadrilateral ACFG
angle EFC + angle FCA + angle CAG + angle AGE = 360
2u + 1u + 1u + 90 + 75 = 360
4u = 195, 1u = 48.75

http://i45.tinypic.com/qstohc.png\">

cheers.

[fanren]

- deleted -

[fxchow]

Hi,


Please help on this P6 math. TIA
If David after giving 1/3 of his money to Ken, Ken will have $70 more than David.
If David after giving 1/5 of his money to Ken, Ken will have $10 money than David. How much does David have initially?

[MathIzzzFun]

fxchow:

Hi,


Please help on this P6 math. TIA
If David after giving 1/3 of his money to Ken, Ken will have $70 more than David.
If David after giving 1/5 of his money to Ken, Ken will have $10 money than David. How much does David have initially?

At first, David --> 15 units (LCM of 3 & 5)

IF David give 1/3 (=5 units) to Ken,
David --> 10 units
Ken --> 10 units + $70
Ken, at first --> 5 units + $70

If David give 1/5 (=3 units) to Ken,

David --> 12 units
Ken --> 8 units + $70

Ken will have $10 more than David

so, 8 units + $70 = 12 units + $10
1 unit --> $15

At first, David --> 15 x $15 = $225

cheers.

[fxchow]

MathIzzzFun:

fxchow:

Hi,


Please help on this P6 math. TIA
If David after giving 1/3 of his money to Ken, Ken will have $70 more than David.
If David after giving 1/5 of his money to Ken, Ken will have $10 money than David. How much does David have initially?

At first, David --> 15 units (LCM of 3 & 5)

IF David give 1/3 (=5 units) to Ken,
David --> 10 units
Ken --> 10 units + $70
Ken, at first --> 5 units + $70

If David give 1/5 (=3 units) to Ken,

David --> 12 units
Ken --> 8 units + $70

Ken will have $10 more than David

so, 8 units + $70 = 12 units + $10
1 unit --> $15

At first, David --> 15 x $15 = $225

cheers.

Hi MathIzzzFun,

Thanks for you reply.

I still can't figure out the below statement.

8 units + $70 = 12 units + $10

Why 12 units + $10? and why both side is equal?

Sorry for so many questions.

[MathIzzzFun]

fxchow:

MathIzzzFun:

[quote=\"fxchow\"]Hi,


Please help on this P6 math. TIA
If David after giving 1/3 of his money to Ken, Ken will have $70 more than David.
If David after giving 1/5 of his money to Ken, Ken will have $10 money than David. How much does David have initially?

At first, David --> 15 units (LCM of 3 & 5)

IF David give 1/3 (=5 units) to Ken,
David --> 10 units
Ken --> 10 units + $70
Ken, at first --> 5 units + $70

If David give 1/5 (=3 units) to Ken,

David --> 12 units
Ken --> 8 units + $70

Ken will have $10 more than David

so, 8 units + $70 = 12 units + $10
1 unit --> $15

At first, David --> 15 x $15 = $225

cheers.

Hi MathIzzzFun,

Thanks for you reply.

I still can't figure out the below statement.

8 units + $70 = 12 units + $10

Why 12 units + $10? and why both side is equal?

Sorry for so many questions.[/quote]
http://i50.tinypic.com/2hyuz9w.png\">

cheers.

[fxchow]

Hi MathIzzzFun,


I got it now. Thank you for your clear picture.