Q&A - PSLE Math

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lizawa:

small:

Thanks for your time...


Q:

The ratio of Roy's money to Samuel's money was 15 : 4. Roy spent $450 and Samuel received $120. Thw new ratio of Roy's money to Samuels money became 5:2. How much money did Roy have at first?

Check the solution here :

http://farm4.static.flickr.com/3033/3299978818_7a5e7a5d28_o.jpg

A million thanks to Lizawa for your fast responds...

[lizawa]

Hi small,


you are welcome. happen to be online

[BlissMom]

http://www.postimage.org/image.php?v=gx1jWTc9



i have recently learnt another method & think it is easier for me to apply. see if it's of any help?

[tianzhu]

Thank you for your time.


1) Mr Lim spent $1496 on some comics and dictionaries altogether. The number of comics bought to the number of dictionaries bought was in the ratio of 3 : 2. A dictionary cost $4 more than a comic. The total cost of the comics was 20% more than the total cost of the dictionaries. Find the cost of a dictionary.

Q2) During a warehouse book sale, Sally spent 62.5% of her money on 24 books and 18 pens. She also spent 25% of her remaining money on 18 files. Each pen costs 8/9 as much as the price of one book. The file costs $7.80 less than a book. Find the total cost of one book and one pen.

[Priskhipo]

tianzhu:

Thank you for your time.


1) Mr Lim spent $1496 on some comics and dictionaries altogether. The number of comics bought to the number of dictionaries bought was in the ratio of 3 : 2. A dictionary cost $4 more than a comic. The total cost of the comics was 20% more than the total cost of the dictionaries. Find the cost of a dictionary.

Q2) During a warehouse book sale, Sally spent 62.5% of her money on 24 books and 18 pens. She also spent 25% of her remaining money on 18 files. Each pen costs 8/9 as much as the price of one book. The file costs $7.80 less than a book. Find the total cost of one book and one pen.

http://www.postimage.org/image.php?v=aV2CpMWA

http://www.postimage.org/image.php?v=Pq2S_FD9

[suiyuan]

Thank you for your help.


Linda brought along $60 to buy a certain number of files. There was a sale in the bookshop and a discount of 20% was given to all items. As a result, Linda was able to buy 6 more files than she would have without the discount.
(a) How many files did Linda buy with the discount given?
(b) What was the price of each file before the discount?

[fudgemum]

[quote]Linda brought along $60 to buy a certain number of files. There was a sale in the bookshop and a discount of 20% was given to all items. As a result, Linda was able to buy 6 more files than she would have without the discount.

(a) How many files did Linda buy with the discount given?
(b) What was the price of each file before the discount?[/quote]20% of $60 is $12.
6 files -> $12
So the cost of 1 file after discount is 12/6 = 2

The total number of files bought after discount is 60/2 = 30

If there is no discount, the number of files she could buy is 30-6 =24.
So the cost of the file before discount is 60/24 = 2.5

(a)30
(b)$2.50

[small]

BlissMom:

http://www.postimage.org/image.php?v=gx1jWTc9



i have recently learnt another method & think it is easier for me to apply. see if it's of any help?

BlissMom, thanks for your help as well..

As for your method, I think the child might get confused how to get 30U = 20U + 600 + 900.

[BlissMom]

Hi Small, c below attempt to explain how to arrive at

30u= 20u+600+900. See if it helps? I prefer this approach which is less lengthy and once the child get the concept, he could work to the solution in shorter steps... at least it worked for my kids


http://www.postimage.org/image.php?v=aV9XQL9

[tweet]

At a stall, Mr Tan sold Alpha watches for $10 each,Beta Watches for $15 each, and Delta Watches for $20 each

The number of Alpha watches sold was 4 times as many as the number of Beta watches sold.
The number of Beta watches sold was twice as many as the number of Delta watches sold.
Mr Tan collected $900 more from the sale of Alpha watches than the sale of Delta Watches.
(a) How much money did Mr Tan collect from the sale of Delta Watches?
(b) How many watches did Mr Tan sell altogether?

:?:
Thanks...........