Q&A - PSLE Math

[jieheng]

Musicstar:

Please help.Thank you


Q11) Sally , Yiling and Ali shared a bag of beads. Sally received 3/4 of the bag of beads and 3/4 of a bead. Yiling received 3/4 of the remaining bag of beads and 3/4 of a bead. Ali received the last bead in the bag. How many beads did Sally receive? (No bead was to be divided in any way)

............................................[---------------1u-------------]
[--------------------3u-------------------][3/4][------3p------][3/4][ 1]
...................................................................[---1p--]

S [--------------------3u-------------------][3/4]
Y [------3p------][3/4]
A [ 1]

1p --> 1 + 3/4 = 7/4
4p --> 7

1u --> 3/4 + 4p = 3/4 + 7 = 31/4

Sally --> 3u + 3/4 = 3*(31/4) + 3/4 = 96/4 = 24

[jieheng]

Musicstar:

Please help.Thank you


Q17 ) Jane and Iris had 255 sweets altogether. Jane had 15 more sweets than Iris. Jane gave away 25% as many sweets as Iris. She was left with twice as many sweets as Iris.
(a) How many sweets did Iris give away?
(b) How many sweets did Jane have in the end?

J [-----------------][15]
I. [-----------------]

J [][---------------][15]
I. [][][][][---------]

J [][----][15][----][15]
I. [][][][][15][----]

J [][][][][15][][][][15] --> 7u + 30
I. [][][][][15][][][] --> 7u + 15

7u + 30 + 7u + 15 --> 255
14u --> 210
1u --> 15

a)

No of sweets that Iris gave away = 4u = 4*15 = 60

b)

No of sweets that Jane had in the end = 6u + 30 = 6*15 + 30 = 120

[Musicstar]

Hi,


Can someonehelp to explain to me my doubt. Why u= 2u -1040 , 4u = 4 (2u-1040 ) & 5u +8u -4160. Thank you very much.

small:

ks2me:

http://i724.photobucket.com/albums/ww246/ks2me/P6MathRiceSacks-1.jpg\">

Thanks again ks2me, you are great...

No wonder I not able to get the answer due to my wrong calculation; 1920 x 5 = 9100.

[Oldschool]

Musicstar:

Hi,


Can someonehelp to explain to me my doubt. Why u= 2u -1040 , 4u = 4 (2u-1040 ) & 5u +8u -4160. Thank you very much.

small:

[quote=\"ks2me\"]http://i724.photobucket.com/albums/ww246/ks2me/P6MathRiceSacks-1.jpg\">

Thanks again ks2me, you are great...

No wonder I not able to get the answer due to my wrong calculation; 1920 x 5 = 9100.

[/quote]
Hi,

There is a difference in the 2 \"u\".

One is small \"u\" and the other is big \"U\".

So, for clarity you can replace one of it with P and it will end up as UP method.

http://www.flickr.com/photos/94858125@N03/8662494378/in/photostream/

Hope this help.

Regards

[MathIzzzFun]

rocklee:

Anyone can help?


There were a total of 20800 toys in Factory A and Factory B. After 3/4 of toys in Factory A and 3/5 in Factory B were sold, there were 1040 more toys in B than A. How many toys were there in each factory at first?

Toys unsold:
Factory A --> 2 units -- 1/4 of total
total in Factory A at first --> 8 units

Factory B --> 2 units + 1040 = 2 x ( 1 unit +520) --- 2/5 of total
total in Factory B at first = 5 x ( 1 unit + 520 ) = 5 units + 2600

At first, total number of toys:
13 units + 2600 = 20800
1 unit --> 1400

At first,
Factory A --> 11 200 toys
Factory B --> 9 600 toys

cheers.

[Musicstar]

How to get 7u each? I do not understand.

jieheng:

Musicstar:

Please help.Thank you

Q17 ) Jane and Iris had 255 sweets altogether. Jane had 15 more sweets than Iris. Jane gave away 25% as many sweets as Iris. She was left with twice as many sweets as Iris.
(a) How many sweets did Iris give away?
(b) How many sweets did Jane have in the end?

J [-----------------][15]
I. [-----------------]

J [][---------------][15]
I. [][][][][---------]

J [][----][15][----][15]
I. [][][][][15][----]

J [][][][][15][][][][15] --> 7u + 30
I. [][][][][15][][][] --> 7u + 15

7u + 30 + 7u + 15 --> 255
14u --> 210
1u --> 15

a)

No of sweets that Iris gave away = 4u = 4*15 = 60

b)

No of sweets that Jane had in the end = 6u + 30 = 6*15 + 30 = 120

[Musicstar]

How to get 7u each? I do not understand.

jieheng:

Musicstar:

Please help.Thank you

Q17 ) Jane and Iris had 255 sweets altogether. Jane had 15 more sweets than Iris. Jane gave away 25% as many sweets as Iris. She was left with twice as many sweets as Iris.
(a) How many sweets did Iris give away?
(b) How many sweets did Jane have in the end?

J [-----------------][15]
I. [-----------------]

J [][---------------][15]
I. [][][][][---------]

J [][----][15][----][15]
I. [][][][][15][----]

J [][][][][15][][][][15] --> 7u + 30
I. [][][][][15][][][] --> 7u + 15

7u + 30 + 7u + 15 --> 255
14u --> 210
1u --> 15

a)

No of sweets that Iris gave away = 4u = 4*15 = 60

b)

No of sweets that Jane had in the end = 6u + 30 = 6*15 + 30 = 120

[MathIzzzFun]

Musicstar:

Please help.Thank you


Q17 ) Jane and Iris had 255 sweets altogether. Jane had 15 more sweets than Iris. Jane gave away 25% as many sweets as Iris. She was left with twice as many sweets as Iris.
(a) How many sweets did Iris give away?
(b) How many sweets did Jane have in the end?

At first,
Iris's sweets --> (255-15) / 2 = 120
Jane's sweets --> 120 + 15 = 135

In the end,
Number of sweets given away, Jane : Iris --> 1 unit : 4 units
Number of sweets left, Jane : Iris --> 2 parts : 1 part

Jane's sweets --> 1 unit + 2 parts = 135 --- (1)
Iris's sweets --> 4 units + 1 part = 120 ----- (2)

(2) x 2 --> 8 units + 2 parts = 240 ---- (3)
(3) - (1) --> 7 units = 105, 1 unit --> 15

1 part --> 120 - 4 x 15 = 60

Number of sweets given away by Iris --> 4 x 15 = 60

Number of sweets Jane had, in the end --> 2 x 60 = 120

cheers.

[YumYum]

Hi, can someone pls help with this question:


Father has given Claire and Jane each a certain amount of money to spend. If Claire spends $30 each day and Jane spends $20 each day, Claire would have $100 left by the time Jane spends all her money. If Claire spends $20 each day and Jane spends $30 each day, Claire would have $600 left by the time Jane spends all her money. Find the total amount of money given to Claire. thks.

[YumYum]

Hi, can someone pls help with this Qn? thks


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