Q&A - PSLE Math

[small]

small:

Thank you for your time.


Question:

Elynn, Fiona and Greg had a total of 336 cards. First Elynn gave Fiona as many cards as Fiona had. Then Fiona gave Greg as many cards as Greg had, and finally Greg gave Elynn as many cards as Elynn had left. In the end, all of them had the same number of cards. How many cards did Elynn have at first? :? :?

Not sure whether this is correct or not, base on my working (model method), Elynn had 154 cards at first.

http://www.postimage.org/Pq1ZN9hr

[ksmama]

Hi small, I used different method: work backwards. The answer is 154 like yours.

[small]

Hi ksmama,


Would you share yours method with us? thanks.

[ksmama]

Hi, not too great with computer but will try to show below. Each step on paper, use arrows to link.


E F G

at the end( 336divide 112 112 112
by 3)


back a step divide by 2 +56
=56 =168


back a step +84 divide by 2
=196 =84


back a step +98 divide by 2
=154 =98

Therefore had E had 154 cards at first.

[ksmama]

Oh no didn’t come out as I had typed. Looks like need microsoft words but see if you can transfer to paper. Write as 3 columns with spacing

back 1st step, the divide by 2=56 is for E. 112+56=168 for G

back 2nd step, 112+84=196 is for F, G is 168 divide by 2=84

back a step, E is 56+98=154, F is 196 divide by2=98

[small]

Hi ksmama,


My way to do this is: type the working in MS word/ excel first, then press/click 'PrtScn' button and paste them to paint brush, modify it and save as picture format, follow by upload to website.

[small]

Thanks for your time.


http://www.postimage.org/image.php?v=Pq2a9RFr

:oops:

[tianzhu]

small:

Thanks for your time.


http://www.postimage.org/image.php?v=Pq2a9RFr

:oops:

The fifth row is
33,35,37,39,41,43,45,47,49

The sixth row is
51,53,55,57,59,,61,63,65,67,69,71

The third number on the sixth row is 55.

b) Find the sum of numbers in the first rows?Anything missing here?

[small]

tianzhu:

small:

Thanks for your time.


http://www.postimage.org/image.php?v=Pq2a9RFr

:oops:

The fifth row is
33,35,37,39,41,43,45,47,49

The sixth row is
51,53,55,57,59,,61,63,65,67,69,71

The third number on the sixth row is 55.

b) Find the sum of numbers in the first rows?Anything missing here?

Thnaks tianzhu, my apologies.the b) part as below:

b) Find the sum of numbers in the first 5 rows?

by the way, can you please share with me how o get the pattern? once again many thanks.

[tianzhu]

Hi

Hope this helps.

http://farm4.static.flickr.com/3425/3372425316_efdc87dfd3_o.jpg\">

Hope my answers are right.