Q&A - PSLE Math

[tianzhu]

Hifive:

Hi tianzhu


Thanks for your advices. Hope I've uploaded correctly. Pls help with this question.


http://www.flickr.com/photos/62186744@N04/5656902661

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Thanks in advance.

Hi

I think you’ve to reinsert your link to the image again.

Best wishes

[small]

Hi,


HTH.

The sum of a,b c, d, e and f is 360 degree.

http://postimage.org/image/zw0v5fwk/

[Hifive]

small:

Hi,


HTH.

The sum of a,b c, d, e and f is 360 degres

http://postimage.org/image/zw0v5fwk/

Hi small

Thanks for your advice and help!

Hi tianzhu

This is the image. Thanks for your help!

[tianzhu]

Hi Hifive


Good Morning.

Hope this helps.

Best wishes.

http://farm6.static.flickr.com/5149/5659052643_4ee8cfe96d_z.jpg\">

[Hifive]

Hi tianzhu


Many thanks for your explanation.

Regards

[tianzhu]

Hifive:

Hi tianzhu


Many thanks for your explanation.

Regards

Hi

You're welcome.

Best wishes.

[andante]

I have encountered the following questions about speed :-


Two people, A and B, were running along a 400-metre oval running track. Thestarted off at the same time, from the same point and ran in the same direction. Person A ran at a speed of 280m/min while person B ran at a speed of 240m/min. How many minutes did Person A take to catch up with Person B?

I don’t really understand the solution provided.

It is mentioned that
For person A to catch up with Person B, he must run one(???) more round than Person B, that is to run an extra 400m. Since Person A covered 280 -240 = 40m more than Person B in each minute, the time he took to catch up with Person B was
400 / (280 - 240) = 10 min

Can someone help to explain ?

Thanks in advance.

[small]

andante:

I have encountered the following questions about speed :-


Two people, A and B, were running along a 400-metre oval running track. Thestarted off at the same time, from the same point and ran in the same direction. Person A ran at a speed of 280m/min while person B ran at a speed of 240m/min. How many minutes did Person A take to catch up with Person B?

I don't really understand the solution provided.

It is mentioned that
For person A to catch up with Person B, he must run one(???) more round than Person B,, that is to run an extra 400m. Since Person A covered 280 -240 = 40m more than Person B in each minute, the time he took to catch up with Person B was
400 / (280 - 240) = 10 min

Can someone help to explain ?

Thanks in advance.

Hi,

HTH..

After one min run, Person A is 40m ahead of Person B, so the distance between them is 360m.
After two min run, Person A is 80m ahead of Person B and now the distance between them is 320m.

For the remaining 320m, Person A will take another 8 min to catch up with Person B.

320 / 40 = 8

So in total Person A took 10 min to catch up with Person B.

[JadeDry]

Hello:


I would appreciate some help with this problem:

Factorize "-ab-9abc" completely.

I am stuck between two answers:

ab(-1-9c)

Or

-ab(1-9c)

I would appreciate it if someone could point out the correct one.

Thanks in advance.

[small]

Hi,


The answer is -ab(1+9c) OR ab(-1-9c).

I personally preferred the first answer.