Q&A - PSLE Math

[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...........

[tianzhu]

Hi

Hope this helps.

http://farm4.static.flickr.com/3450/3308323625_bba06ca21f_o.jpg\">

[ChiefKiasu]

tianzhu:

Hi

Hope this helps....

tianzhu, I totally impressed! :shock: :shock:
:udaman:

[tweet]

Hello Tianzhu

Thank you so much for such a wonderful and clear table.Will explain to my son today.Once again,thanks!

[small]

Hi tianzhu , thanks for the solution.



(80*15)/10 which is same as 8U = 8 * 15 = 120.

[mHeu]

check out http://unittransfermethod.blogspot.com

i think they have similar questions there with an alternative way to solve it...logical, systematic and neat, based on the fundamentals of ratio. nice

[tianzhu]

More P6 questions from CNA forum.You may go to this site.

( http://www.channelnewsasia.com/discussion/forum.htm )

1. Courier A takes 10 hours to deliver a parcel from Town X to Town Y. Courier B takes 12 hours to deliver the parcel along the same route. If the speed of Courier A is 9km/h faster than that of Courier B, find the speed of Courier A.

2. There were some apples at a fruit stall. In the morning, the number of apples sold was 2/5 of the apples left. In the afternoon, another 44 apples were sold. The total number of apples sold was 6 less than 9/14 of the number of apples the fruit stall had at first. How many apples were there at first?

3. In a grooming workshop organised by the school, 75% of the pupils participated were girls. 49 girls and 3 boys quitted halfway and went home. The remaining pupils were organised into groups of 10 for group discussion. There were 3 boys in each group. How many pupils participated in the grooming workshop at first?

4. There were some apples and oranges in a box. 80% of the fruits in the box were apples. Ali sold 63 apples and 9 oranges. He packed the remaining fruits into packets of 12 apples and oranges. Each packet of fruits has 3 oranges. Find the total number of oranges Ali had at first.

5. When Mrs Lee was 40 years old, her son was twice her daughter's age. Mrs Lee will be twice her son's age when her daughter is 28 years old. How old will Mrs Lee be when her daughter is 20 years old?

6. In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?

7. Tom wants to complete a jigsaw puzzle. On the first day, he fitted 20% of the puzzle. On the second day he fitted another 60 pieces. The ratio of fitted to non-fitted pieces is now 2:5. How many pieces are there in the jigsaw puzzle?

8. Shop X sells a watch for $2400 which is 25% less than what Shop Y sells. During a sale, both shops offer an equal percentage discount. Mr Lee bought the watch in Shop Y and paid $520 more than the discounted price in Shop X. What is the percentage discount given by both shops?

9. The ratio of Ryan's pocket money to John's pocket money was 3 : 2. After Ryan saved $15 and John spent $8, the ratio of Ryan's pocket money to John's pocket money was 3 : 1. How much money did Ryan have at first?