Q&A - PSLE Math

[MathIzzzFun]

pixiedust:

Appreciate any help with this :

http://i1197.photobucket.com/albums/aa424/pixie_dust8/mq9.jpg\">

Hi

hope this helps..

http://i47.tinypic.com/2chrlup.png\">

cheers.

[jonaandr]

please help to solve this problem, thanks advance!


1. Jason, Edward and Sam had a total of $837. Jason had the least amount of money. the ratio of Edward’s money to sam’s money ws 4:3 at first. Jason and Edward each spent 1/3 of their money. Given that the three boys had $648 left, how much did jason have at first?

[peggy]

jonaandr:

please help to solve this problem, thanks advance!


1. Jason, Edward and Sam had a total of $837. Jason had the least amount of money. the ratio of Edward's money to sam's money ws 4:3 at first. Jason and Edward each spent 1/3 of their money. Given that the three boys had $648 left, how much did jason have at first?

Let me try.

At first,
Jason ---- 3 p
Edward ---- 12 u
Sam ---- 9 u

Spent,
Jason ---- 1 p
Edward ---- 4 u

837 - 648 = 189 (spent by Jason and Edward)

1 p + 4 u = 189 **
3 p + 21 u = 837 total amount at first

equalise,
3 p + 12 u = 567 **
3 p + 21 u = 837

9 u --- 270
1 u --- 30

1 p + (4 x 30) = 189
1 p = 69 hence, Jason has 69 x 3 = 207 at first

Hope I'm right.

[jonaandr]

peggy:

jonaandr:

please help to solve this problem, thanks advance!


1. Jason, Edward and Sam had a total of $837. Jason had the least amount of money. the ratio of Edward's money to sam's money ws 4:3 at first. Jason and Edward each spent 1/3 of their money. Given that the three boys had $648 left, how much did jason have at first?

Let me try.

At first,
Jason ---- 3 p
Edward ---- 12 u
Sam ---- 9 u

Spent,
Jason ---- 1 p
Edward ---- 4 u

837 - 648 = 189 (spent by Jason and Edward)

1 p + 4 u = 189 **
3 p + 21 u = 837 total amount at first

equalise,
3 p + 12 u = 567 **
3 p + 21 u = 837

9 u --- 270
1 u --- 30

1 p + (4 x 30) = 189
1 p = 69 hence, Jason has 69 x 3 = 207 at first

Hope I'm right.

Thank you very much!

[tianzhu]

Michaelia0816:

Tianzhu, pls help with this question, it is from the CBS paper.


2) http://t.co/DhdNHZqU ( read the caption)

Hi girl

Q2

There are a few approaches.

The total number of pages in the book remains the same before and after. Hence, make the total number of units the same.

Case 1

Number of pages read: Number of pages unread ------- 2:5 (7) -------- 18:45 (63)

Case 2

Number of pages read: Number of pages unread ------- 4:5 (9) -------- 28:35

10 units ------- 40

1 unit -------- 4

Total number of pages -------- 63*4 -------- 252

Best wishes

[Michaelia0816]

There is my Q1. Sorry for the empty spaces on the question! http://i45.tinypic.com/10i80gn.jpg\">

[Michaelia0816]

How to do this question , i cannot solve it,


4. A store had a 20% storewide discount on all items purchased. On the last day of sale, a further discount of 15% was given to all customers. Mdm Ong brought a handbag for $93.50 on the last day. What the original price of the handbag?

[tianzhu]

Michaelia0816:

How to do this question , i cannot solve it,


4. A store had a 20% storewide discount on all items purchased. On the last day of sale, a further discount of 15% was given to all customers. Mdm Ong brought a handbag for $93.50 on the last day. What the original price of the handbag?

Q1

Break up the question into steps. A simple diagram may help you to see better.

85% ------- 93.50

100% ------- 110 (price before the further 15% discount)

$110 is also the price after the 20% discount.

Original cost -------110*100/80 ------- 137.5

Best wishes

[niza6666.028774hotmail.028774com]

Please help me. Thanks in advance.

There were 180 boys and girls in the canteen. When 5/8 of the boys and 1/2 of the girls left the canteen, the number of boys and girls who remained became 80. How many boys were there in the canteen at first?

[tianzhu]

mn:

Please help me. Thanks in advance.

There were 180 boys and girls in the canteen. When 5/8 of the boys and 1/2 of the girls left the canteen, the number of boys and girls who remained became 80. How many boys were there in the canteen at first?

Hi

This question touches on simultaneous concept.

You may solve it in a pictorial manner using MD, or represent the variables with units and parts or letters of the alphabet.

Boys

Left ------ 5B

Remained -------- 3B

Girls

Left ------- 1G

Remained -------- 1G

5B + 1G -------- 100(180-80)

3B + 1G ------- 80

2B ------- 20 (100-80)

B -------- 10

3*10 +1G ------- 80

1G -------- 50

Number of boys@first ------- 80 (8*10)

Best wishes