Q&A - PSLE Math

[Spongy]

Hi, I need help with 2 questions. Thanks.


1. Tina had $216 and Charlie had $184. Charlie spent 3 times as much as Tina and after that, Tina had 3 times as much money left as Charlie. How much did Charlie spend?

2. Mrs Tan went shopping with 46 more $5-notes than $2-notes. After using 70 of her $5-notes, she found that she had 4 times as many $2-notes as $5-notes. Find the total amount of money she had at first.

[tianzhu]

Spongy:

Hi, I need help with 2 questions. Thanks.

1. Tina had $216 and Charlie had $184. Charlie spent 3 times as much as Tina and after that, Tina had 3 times as much money left as Charlie. How much did Charlie spend?

Hi

You may use MD or represent the variables with “Units and Parts” or letters of the alphabet.

Spent
Tina ------ 1 unit
Charlie ------ 3 units

Left
Tina ------ 3 parts
Charlie ------ 1 part

3 parts + 1 unit ------ 216
1 part + 3 units ------ 184

4 parts + 4 units ------ 400
1 part + 1 unit ------ 100

2 units ------ 184 - 100
1 unit ------- 42

Charlie ------ 3*42 -------- 126

Best wishes

[tianzhu]

Spongy:

Hi, I need help with 2 questions. Thanks.

2. Mrs Tan went shopping with 46 more $5-notes than $2-notes. After using 70 of her $5-notes, she found that she had 4 times as many $2-notes as $5-notes. Find the total amount of money she had at first.

Hi

Hope this helps.

Best wishes

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[Spongy]

Thank you very much:-D

[tianzhu]

Spongy:

Thank you very much:-D

Hi

You're welcome.

Best wishes

[yomamas]

CRAZYBANANA:

jarenchuatw:

Thanks...but still can't really understand the 2nd part added on:


After 43x27=1161 rectangles have been For the width 166cm, there is a leftover of 166 - 27x6 = 4cm
Of which, 173/6 = 28 (round down) more rectangles can be cut.
Total = 1161 + 28 = 1189

Tot that we have already cut out some rectangles from 173, how come can still divide by 6 again??

Ya! Since the 173cm side has been cut into 43pc x4cm, then balance is only 1cm, cannot use liao! :?

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[jarenchuatw]

Can someone explain the question below again? I can’t seem to understand this particular part


Brought both parents } 8 units - 3 units
Did not bring parents } = 5 units

At a prize-giving ceremony, prize-winners could invite either one or both of their parents to attend. The ratio of the number of prize-winners to the number of parents who attended was 8:11 and 3/8 of the prize-winners bought only one parent. What fraction of the prize-winners did not have any parents attending the ceremony?

Prize Winners = 8 units
Parents = 11 units

Out of prize winners (8 units), there are 3 groups:
Brought 1 parent = 3/8 of 8 units = 3 units; 3 units x 1 parent = 3 units of parents
Brought both parents } 8 units - 3 units
Did not bring parents } = 5 units

Now, looking at the parents:
11 units - 3 units = 8 units
8 units of parents belong to those who brought BOTH parents.

Prize Winners (brought both parents & did not bring parents):
Brought both parents: 8 units of parents divide by 2 parents per prize winner = 4 units of prize winners
5 units - 4 units = 1 unit of prize winners did not bring parents

1 out of 8 prize winners did not bring their parents. (Ans: 1/8)

[tianzhu]

Hi


This question has been discussed before.

Best wishes

http://farm8.staticflickr.com/7271/7140764163_e0d3192e22_z.jpg\">

[concern_mum]

hi all


I have below question from Nan Hua Pr Sch 2011 SA1 question, can someone help me.


1. Town A and town B were 395km a part. A 6am, a car started travelling from Town A to Town B at a constant speed of 60km/hr. At 6.20am a motocycle started travelling from town B to Town A at a constant speed of 90km/hr.

a. At what time did they pass each other?
b. How far away was the car from Town B when it passed the motocycle?

2. Cindy had four times as many postcards as Annie. After Cindy gave 20% of her postcards to Jane and Annie gave 10% of her postcards to Jane, the number of Jane’s postcards increased by 75%. Jane had 252 postcards in the end. How many postcards did Cindy have at first?

[tianzhu]

concern_mum:

hi all


I have below question from Nan Hua Pr Sch 2011 SA1 question, can someone help me.


1. Town A and town B were 395km a part. A 6am, a car started travelling from Town A to Town B at a constant speed of 60km/hr. At 6.20am a motocycle started travelling from town B to Town A at a constant speed of 90km/hr.

a. At what time did they pass each other?
b. How far away was the car from Town B when it passed the motocycle?

Hi

For speed questions, it’s useful to start with a simple diagram.

In 20 minutes, the car covered 1/3*60 ------- 20 km

395 – 20 ------- 375

375/ (60+90) -------- 2.5

(a)2.5h from 6.20am --------- 8.50am

(b)90*2.5 ------- 225 km

Best wishes