Tutor MathsGuru: Ask me for your burning Maths questions!

[charsen]

Hi Mathguru,


Kindly help me with my math problem.
Colin and Rosdin had the same amount of pocket money. Each day, Colin spent $12 and Rosdin spent $15. When Rosdin had $18 left Colin had 5 times as much money left as Rosdin. How much was each boy’s pocket money?

It will be of great help if you show me the solution by model method.

TIA
charsen

[Yu Xuan]

charsen:

Hi Mathguru,


Kindly help me with my math problem.
Colin and Rosdin had the same amount of pocket money. Each day, Colin spent $12 and Rosdin spent $15. When Rosdin had $18 left Colin had 5 times as much money left as Rosdin. How much was each boy's pocket money?

It will be of great help if you show me the solution by model method.

TIA
charsen

Not a guru, but this is my solution while waiting for the model solution;

Difference in their spending per day --> $15 - $12 = $3
Difference in their money --> $18 * 4 = $72

To find out the number to days of spending in order to arrive at a situation when Colin has $72 more than Rosdin,
$72 / $3 = 24 days

Hence, their pocket money is;
Using Rosdin
( $15 * 24 ) + $18 = $378
Alternatively, using Colin;
( $12 * 24 ) + ( $18 * 5) = $378

[autolycus]

charsen:

Hi Mathguru,


Kindly help me with my math problem.
Colin and Rosdin had the same amount of pocket money. Each day, Colin spent $12 and Rosdin spent $15. When Rosdin had $18 left Colin had 5 times as much money left as Rosdin. How much was each boy's pocket money?

It will be of great help if you show me the solution by model method.

TIA
charsen

Each day, Colin is saving $3. Per day, it looks like this.

Colin: UUUU3
Rosdin: UUUUU

Colin is spending 4U per day, Rosdin is spending 5U per day. Each U is $3.

At the end, Rosdin has $18, Colin has 5 x $18 = $90.

So how many Us were there?

Colin has 30U saved.
Rosdin has 6U saved.

Since Colin has been saving 1U per day, he has been saving for 24 days if he has that much more than Rosdin.

So Colin had 24 UUUU + 90 = 24(12) + 90 = $378
Rosdin had 24 UUUUU + 18 = 24(15) + 18 = $378

Actually, it's horrible not being able to draw these things, and the model is not as easy as just to think of it this way:

Colin has saved $72 more than Rosdin and he is saving $3 a day.
That means 72/3 = 24 days of saving.
So Colin had 24x12 + 90 = $378.
Rosdin had the same amount at the beginning = $378.

[mathsguru]

charsen:

Hi Mathguru,


Kindly help me with my math problem.
Colin and Rosdin had the same amount of pocket money. Each day, Colin spent $12 and Rosdin spent $15. When Rosdin had $18 left Colin had 5 times as much money left as Rosdin. How much was each boy's pocket money?

It will be of great help if you show me the solution by model method.

TIA
charsen

Hi Charsen,

Happy CNY to you! Saw your PM and I've have done up the solutions but can't send them to you over PM, hence posting them here.

Hope they help!

Cheers,
MathsGuru

http://postimage.org/image/4if5r8o4/

http://postimage.org/image/4iigtxno/

http://postimage.org/image/1suajbv0k/

[mathsguru]

Dear all,


Happy Chinese New Year to you and your loved ones!! :please:

Sincerely apologise for not being as active in this forum as I want for the past months. Have been tied up with renovation stuff amidst my tuition classes. Although I've my wedding preparations coming up in the next few months, I hope to be able to contribute more in time to come.

Appreciate the other members who have been sharing their solutions selflessly and tirelessly all this while.

Here's wishing everyone a great year ahead!! :celebrate:


MathsGuru

[autolycus]

mathsguru:

Dear all,


Happy Chinese New Year to you and your loved ones!! :please:

Sincerely apologise for not being as active in this forum as I want for the past months. Have been tied up with renovation stuff amidst my tuition classes. Although I've my wedding preparations coming up in the next few months, I hope to be able to contribute more in time to come.

Appreciate the other members who have been sharing their solutions selflessly and tirelessly all this while.

Here's wishing everyone a great year ahead!! :celebrate:


MathsGuru

Happy Rabbit Year to you too! I must say that I come here to learn what PSLE math looks like these days, and it's a good place for that.

[tinasen]

Dear MathGuru,

It was my son who posted these questions since he could not get a satisfactory help from his own private tutor.
Your solution with explanations are mind blowing. Hats off to you!
I'm sure many struggling parents like me are benefiting from this forum.
God bless for this volunteer service.

Wish you a very Happy and prosperous Rabbit Year.

- Thanks
Tinasen

mathsguru:

charsen:

Hi Mathguru,

Kindly help me with my math problem.
Colin and Rosdin had the same amount of pocket money. Each day, Colin spent $12 and Rosdin spent $15. When Rosdin had $18 left Colin had 5 times as much money left as Rosdin. How much was each boy's pocket money?

It will be of great help if you show me the solution by model method.

TIA
charsen

Hi Charsen,

Happy CNY to you! Saw your PM and I've have done up the solutions but can't send them to you over PM, hence posting them here.

Hope they help!

Cheers,
MathsGuru

http://postimage.org/image/4if5r8o4/

http://postimage.org/image/4iigtxno/

http://postimage.org/image/4ilrwmn8/

[tinasen]

Hi MathGuru,

For Q3 \"Millie and Ronnie had a total of $338. After Millie saved $49 and Ronnie spent half of her money,they both had the same amount of money. How much did Millie have at first?\"
As it is stated Millie \"Saved\" $49 I got the following answer which is diffrent from yours. May be I'm wrong.

2*49 = 98
338-98 = 240
240/2 = 120
The final answer I got was 120.

- Tinasen

mathsguru:

charsen:

Hi Mathguru,

Kindly help me with my math problem.
Colin and Rosdin had the same amount of pocket money. Each day, Colin spent $12 and Rosdin spent $15. When Rosdin had $18 left Colin had 5 times as much money left as Rosdin. How much was each boy's pocket money?

It will be of great help if you show me the solution by model method.

TIA
charsen

Hi Charsen,

Happy CNY to you! Saw your PM and I've have done up the solutions but can't send them to you over PM, hence posting them here.

Hope they help!

Cheers,
MathsGuru

http://postimage.org/image/4if5r8o4/

http://postimage.org/image/4iigtxno/

http://postimage.org/image/4ilrwmn8/

[mathsguru]

tinasen:

Hi MathGuru,

For Q3 \"Millie and Ronnie had a total of $338. After Millie saved $49 and Ronnie spent half of her money,they both had the same amount of money. How much did Millie have at first?\"
As it is stated Millie \"Saved\" $49 I got the following answer which is diffrent from yours. May be I'm wrong.

2*49 = 98
338-98 = 240
240/2 = 120
The final answer I got was 120.

- Tinasen

Hi Tinasen,

Sorry, I've read the question wrongly! Haha...instead of saved $49, I read it as soent $49! Ooopsss...No wonder I thought my answer looks quite weird with fraction in it! Correct answer should be $80.

Here's the amended solution:

http://postimage.org/image/1ssi1dbr8/

Cheers,
MathsGuru

[tinasen]

Thank you Math Guru.

mathsguru:

tinasen:

Hi MathGuru,
For Q3 \"Millie and Ronnie had a total of $338. After Millie saved $49 and Ronnie spent half of her money,they both had the same amount of money. How much did Millie have at first?\"
As it is stated Millie \"Saved\" $49 I got the following answer which is diffrent from yours. May be I'm wrong.

2*49 = 98
338-98 = 240
240/2 = 120
The final answer I got was 120.

- Tinasen

Hi Tinasen,

Sorry, I've read the question wrongly! Haha...instead of saved $49, I read it as soent $49! Ooopsss...No wonder I thought my answer looks quite weird with fraction in it! Correct answer should be $80.

Here's the amended solution:

http://postimage.org/image/1ssi1dbr8/

Cheers,
MathsGuru