Q&A - PSLE Math

[maychang]

oliveminx:

JE382:

One more question :

In the figure that is not drawn to scale, ABCF is a rectangle. Find the area of the shaded parts.
http://i44.tinypic.com/10s9jfb.png\">

Did u draw this diagram yourself or was it scanned from the original question?

Hi Oliveminx,
Thanks for your reply.
JE382 is my DD, she is going to sit for psle next year.
She draws the diagram herself as we do not have a scanner at home.
Will get her to repost the diagram in bigger size.

[JadeDry]

Hello,


I would appreciate input on the following question-

Make b the subject of the formula

((a squared) / (x squared)) + ((b squared) / (y squared)) = 1

My answer is ( b= square root of (y squared( x squared - a squared)) / (x squared)

Is this correct?

Thanks in advance.

[MathIzzzFun]

JadeDry:

Hello,


I would appreciate input on the following question-

Make b the subject of the formula

((a squared) / (x squared)) + ((b squared) / (y squared)) = 1

My answer is ( b= square root of (y squared( x squared - a squared)) / (x squared)

Is this correct?

Thanks in advance.

Hi

http://i39.tinypic.com/1zqsw7t.jpg\">

btw, is this p6/psle maths ? I would suggest that you post this at the secondary maths thread in order not to confuse P6 parents/P6 students who are reading this thread.

cheers.

[oliveminx]

5) At first, Ravi had $200 more than Vincent. He gave 40% of his money to Vincent. Vincent then gave 25% of his money to Ravi. In the end, Vincent had $68 more than Ravi. How much did Vincent give Ravi?


R[100%][200]
V[100%]

R[60%][ 120 ]
V[140%][80]

R[95%][140]–68-
V[ 105% ][60]

10%=208-60=148
35%=518
518+20=538

[just888]

JE382:

One more question :

In the figure that is not drawn to scale, ABCF is a rectangle. Find the area of the shaded parts.
http://i44.tinypic.com/10s9jfb.png\">

http://i41.tinypic.com/2jciloo.png\">

Name the line intersection point of AD and BE line G
Area of shaded area x
= Area of triangle BDG
= Area of triangle ADB - Area of the triangle AGB
= (1/2 x 12 x 9) - (1/2 x 12 x 7)
= 54 - 42
= 12

Area of the shaded area y
= Area of triangle AEG
= Area of triangle AEB - Area of triangle AGB
= (1/2 x 12 x 9) - (1/2 x 12 x 7)
= 54 - 42
= 12

Area of the shaded parts
= Area of the x + Area of y
= 12 + 12
= 24

[oliveminx]

maychang:

Hi Oliveminx,
Thanks for your reply.
JE382 is my DD, she is going to sit for psle next year.
She draws the diagram herself as we do not have a scanner at home.
Will get her to repost the diagram in bigger size.

I think BD and AE are supposed to be straight lines. If so, the two solutions posted are correct.

[JE382]

tianzhu:

JE382:

One more question :

In the figure that is not drawn to scale, ABCF is a rectangle. Find the area of the shaded parts.
http://i44.tinypic.com/10s9jfb.png\">

Hi

It’s helpful to have a bigger image.Is line BE a straight line?

In answering this question, I assume that line BE is a straight line
The two shaded areas are of equal sizes.

Area of triangle ABD ----- ½ * 12 * 9 ------ 54
Area of triangle (height 7 cm) ----- ½ * 12 * 7 ------ 42

Difference of 1 shaded part ------ 54 – 42 -----12
Area of 2 shaded parts ------ 12*2 ----- 24

Best wishes

Yes, line BE is a straight line. Thanks for your answer too!
:thankyou:

[JE382]

Thanks to everyone who have answered my questions!!

[tianzhu]

JE382:

Yes, line BE is a straight line. Thanks for your answer too!
:thankyou:

Hi

You're welcome.

Best wishes

[elkniwt]

Hi,


Like to ask a general question on \"part thereof\" :

For qns like, (make-up qn, so forgive me for any phrasing error.. )
Cost of postage is $10 for the first 100g and $2 for the subsequent additional 10g. What is the cost of postage for a 123g parcel?

Please advise what is the difference in answer (if any) with or without the phrase \"part thereof\".

Thank you very much.