## Q&A - PSLE Math

### Re: Q&A - PSLE Math

Hi! Need help with this qns. Thanks!

Peter had some $2 notes and $5 notes. He spent 50% of the $2 notes and 3/5 of his $5 notes. The value of the $2 notes left was the same as the value of the $5 notes left. The difference between the value of the $2 notes and the value of the $5 notes he had at first was $45. How much did Peter have at first?

Peter had some $2 notes and $5 notes. He spent 50% of the $2 notes and 3/5 of his $5 notes. The value of the $2 notes left was the same as the value of the $5 notes left. The difference between the value of the $2 notes and the value of the $5 notes he had at first was $45. How much did Peter have at first?

### Re: Q&A - PSLE Math

vvv

A: 1705617

Subject: Math

Level: P6

Tags: Fraction, Percentage, u and p

Source:

^^^

At first, Let the number of $2 notes be 2u. And the number of $5 notes be 5p

Value of $2 notes = 2u X $2 = $4u

Value of $5 notes = 5p X $5 = $25p

$25p - $4u = $45 -----(1)

After spending 1/2 of $2 notes and 3/5 of $5 notes, value of $2 notes and $5 notes left are the same.

$2u = $10p

Substitute (2u=10P) into (1)

$25p - $20p = $45

p = 9

2u = 10p

2u = 90

u = 45

At first,

Value of $2 notes = $4u = $180

Value of $5 notes = $25p = $225

Total at first = $180 + $225 = $405

A: 1705617

Subject: Math

Level: P6

Tags: Fraction, Percentage, u and p

Source:

^^^

At first, Let the number of $2 notes be 2u. And the number of $5 notes be 5p

Value of $2 notes = 2u X $2 = $4u

Value of $5 notes = 5p X $5 = $25p

$25p - $4u = $45 -----(1)

After spending 1/2 of $2 notes and 3/5 of $5 notes, value of $2 notes and $5 notes left are the same.

$2u = $10p

Substitute (2u=10P) into (1)

$25p - $20p = $45

p = 9

2u = 10p

2u = 90

u = 45

At first,

Value of $2 notes = $4u = $180

Value of $5 notes = $25p = $225

Total at first = $180 + $225 = $405

- ninjamathtv
- YellowBelt
**Posts:**15**Joined:**Thu May 19,

### Re: Q&A - PSLE Math

This question can be easily solved by using the bar model method, part and whole concept. Watch the step by step video below:SOS mum wrote:Sorry, 2 more. Many tks and God Bless:)

2) Three children, Sally, Lynn and Penny have different amounts of money.

The amount of money Lynn has is the total of Sally and Penny's amount.

The amount of money Penny has is the total of Sally's amount and half of Lynn's amount, Sally has $14.

(a) How much does Lynn have?

(b) How much do these three children have altogether?

[/youtube]

### Re: Q&A - PSLE Math

Leah_ wrote:Hi! Need help with this qns. Thanks!

Peter had some $2 notes and $5 notes. He spent 50% of the $2 notes and 3/5 of his $5 notes. The value of the $2 notes left was the same as the value of the $5 notes left. The difference between the value of the $2 notes and the value of the $5 notes he had at first was $45. How much did Peter have at first?

An alternative solution:

<---$-left----><----$-spent-------->

---<--50%-->

$2 (----2u----)(------2u-----)<-45-> <----$45 is the difference at first

$5 (--u--)(-u-)(--u--)(--u---)(--u---)

----<-- 2/5--><--------3/5--------->

Hence u-> 45

**Peter has 9u at first => 9x45 = $405**

### Re: Q&A - PSLE Math

Hi, anyone can help? Tks in advance.

The ratio of the number of Larry's marbles to the number of John's marbles was 3:5. In a game with their friends, Larry won 15 marbles while John lost 3 marbles. They both then had the same number of marbles. How many marbles did both boys have altogether before the game?

The ratio of the number of Larry's marbles to the number of John's marbles was 3:5. In a game with their friends, Larry won 15 marbles while John lost 3 marbles. They both then had the same number of marbles. How many marbles did both boys have altogether before the game?

### Re: Q&A - PSLE Math

Time--------Larry----JohnNickal wrote:Hi, anyone can help? Tks in advance.

The ratio of the number of Larry's marbles to the number of John's marbles was 3:5. In a game with their friends, Larry won 15 marbles while John lost 3 marbles. They both then had the same number of marbles. How many marbles did both boys have altogether before the game?

Before--------3u-------5u

After--------3u+15-----5u-3

3u+15=5u-3

2u=18

u=9

Before total is 8u..

**Hence 8x9=72 marbles**

- ninjamathtv
- YellowBelt
**Posts:**15**Joined:**Thu May 19,

### Re: Q&A - PSLE Math

To make this question easier to understand, you can draw bar models like the video below:Nickal wrote:Hi, anyone can help? Tks in advance.

The ratio of the number of Larry's marbles to the number of John's marbles was 3:5. In a game with their friends, Larry won 15 marbles while John lost 3 marbles. They both then had the same number of marbles. How many marbles did both boys have altogether before the game?

[/youtube]

### Re: Q&A - PSLE Math

BigDevil wrote:vvv

A: 1696145

Subject: {Math}

Level: {P6}

Tags: {Speed}

Source: {}

^^^belnanna wrote:

At 24min(o.4hr), Peter reached. meaning dave covered 2km lesser in 0.4hr.

therefore distance between town a n b = 0.4 x 70 + 2=30km

Peter speed = 30/0.4 hr = 75km/h

### Re: Q&A - PSLE Math

Your solution completely ignore the "6 minutes after they pass each other". If you considered this information, the whole question is flawed.Dr.Ta wrote:BigDevil wrote:vvv

A: 1696145

Subject: {Math}

Level: {P6}

Tags: {Speed}

Source: {}

^^^belnanna wrote:

At 24min(o.4hr), Peter reached. meaning dave covered 2km lesser in 0.4hr.

therefore distance between town a n b = 0.4 x 70 + 2=30km

Peter speed = 30/0.4 hr = 75km/h