Tutor MathsGuru: Ask me for your burning Maths questions!

[mathsguru]

suiyuan:

1) Terry walks to school at an average speed of 4km/h every day. One day, after walking a distance of 1km, he realised that his watch was slow. So, he ran at a constant speed and managed to reach the school just on time. Later, he calculated that if he had run at this speed right from the start of the journey, he would have reached school 5 minutes earlier. What was his running speed?


2) Amy took 3 hours to travel from Town P to Town Q. Pansy took 2 hours to travel from Town Q to Town P. Both of them started travelling at 9am. At what time did they pass each other?

3) 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.

4) Lily is meeting a friend at a certain time. If she drives at 80 km/h, she will be 1/3 hour late. If she drives at 60 km/h, she will be 3/4 hour late. How long will the journey take if she drives at 90 km/h?

5) Simon cycled at an average speed of 10km/h from his house to the park. On reaching the park, he cycled back home along the same route at an average speed of 8km/h. He took 1h 12 mins for the entire journey. How long did he take to cycle from the park back to his home?

Dear Suiyuan,

Here are my detailed solutions. A useful tip to note for speed questions is that speed and time are inversely proportional. So, many a time, for questions without much details, we can solve them by comparing their ratio for speed and inversing it to get ratio for time, and vice-versa.

Hope my workings and diagrams are clear enough!

Regards,
MathsGuru

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http://www.postimage.org/image.php?v=Pq1NCVHi

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[KSP]

tamarind:

Dear all who replied to my question,

My friend said it is from an assessment book. The answer is not 175.

I just wanted to confirm that there is something wrong with this question. The publisher need to correct this mistake.

Either the question or answer is wrong.

[KSP]

I feel that to help our kids do well in Maths, we have to let them learn how to solve these mind twisting questions. Some of the PSLE Maths questions even we as parents can’t solve them. I feel that schools are not doing enough in this area.


While we can share our workings and solutions here, but when come to explaining to our kids they may not understand or take a while to absorb. I’m not sure this is the right approach. But I still think there should be a proper method in teaching our kids to solve model questions.

Is there anyone here watch the Friday night 10.30pm Ch8 show about the P6 student saying how tough the PSLE Maths paper.

The thing that interest me was when they asked the HCI and NYGH students to solve the "Ken Jim chocolate sweet" question, one of the NYGH said she already know how to answer this type of question when she was P5 and she learnt it at an enrichment class. So I really wonder which enrichment class teaches this. Is it Learning Lab, Dr Peh or etc… can do the job?

[lizawa]

KSP:

I feel that to help our kids do well in Maths, we have to let them learn how to solve these mind twisting questions. Some of the PSLE Maths questions even we as parents can't solve them. I feel that schools are not doing enough in this area.


While we can share our workings and solutions here, but when come to explaining to our kids they may not understand or take a while to absorb. I'm not sure this is the right approach. But I still think there should be a proper method in teaching our kids to solve model questions.

Is there anyone here watch the Friday night 10.30pm Ch8 show about the P6 student saying how tough the PSLE Maths paper.

The thing that interest me was when they asked the HCI and NYGH students to solve the \"Ken Jim chocolate sweet\" question, one of the NYGH said she already know how to answer this type of question when she was P5 and she learnt it at an enrichment class. So I really wonder which enrichment class teaches this. Is it Learning Lab, Dr Peh or etc.... can do the job?

I believe the top class students are exposed to this type of question and they should be able to do them. My P5 girl attends Maths supplementary class in school and her teacher teaches them Algebra, which is not in the P5 syllabus. But this is only for selected classes.

[Dharma]

lizawa:

I believe the top class students are exposed to this type of question and they should be able to do them. My P5 girl attends Maths supplementary class in school and her teacher teaches them Algebra, which is not in the P5 syllabus. But this is only for selected classes.

Agree w/ you, lizawa. If they are not done in P5, likely to be covered in P6.

[tianzhu]

Hi Chiefkiasu


I observe that mathsguru has been active in her responses to queries. Would it be possible to make her thread a sticky one or place her thread as one of subset of PSLE Maths? Otherwise it will be a waste if her thread disappears from the radar screen.

It will certainly benefit parents/students in the long run if she continues to be active in answering questions. Of course, this arrangement will only stay if she is active.

Best wishes

[all.013398in.013398one]

Thanks for MathGuru's commitment in Math solutions!

Perhaps it is good to indicate which level is the questions posted.
Or are these all PSLE P6 questions only? :thankyou:

[Muffins]

tianzhu:

Hi Chiefkiasu


I observe that mathsguru has been active in her responses to queries. Would it be possible to make her thread a sticky one or place her thread as one of subset of PSLE Maths? Otherwise it will be a waste if her thread disappears from the radar screen.

It will certainly benefit parents/students in the long run if she continues to be active in answering questions. Of course, this arrangement will only stay if she is active.

Best wishes

You're right Tianzhu, Mathsguru's thread should be a sticky for more efficiency in going into her thread, to see the problems she has solved!

Mathsguru, you are a very commited kiasuparenter, and thank you for all the sums you have solved so far! :thankyou: :udawoman:

[Tang]

Muffins:

Seekinghelp:

Ty Muffins, Tutormum and Mathsguru for ans! Now i understand how to do it.


Next ques: The sum of two numbers is 15 but the difference is 7. Find the bigger number.

It seems like I'm the only one who keep asking ques :lol: Paisey.
I know the ans is 11 but i duno hw to guide him thru explanation.

Hi Seekinghelp, the problem can be solved in two ways. Both, easy to understand and explain. I'll give both of them.

The first way
15 - 7 = 8
8/2 = 4
15 - 4 = 11

The second way is longer but easier to explain...
Bigger number + smaller number = 15
Bigger number - smaller number = 7

So, bigger number + smaller number + bigger number - smaller number = 15 + 7 = 22

Which is the same as bigger number + bigger number = 22

So 1 of the bigger numbers is 22/2 = 11

Hope I helped!

To get the bigger number (big unit), do addition instead of subtraction.

15 + 7 = 22
22/2 = 11

[tutormum]

Tang:

Muffins:

[quote=\"Seekinghelp\"]Ty Muffins, Tutormum and Mathsguru for ans! Now i understand how to do it.


Next ques: The sum of two numbers is 15 but the difference is 7. Find the bigger number.

It seems like I'm the only one who keep asking ques :lol: Paisey.
I know the ans is 11 but i duno hw to guide him thru explanation.

Hi Seekinghelp, the problem can be solved in two ways. Both, easy to understand and explain. I'll give both of them.

The first way
15 - 7 = 8
8/2 = 4
15 - 4 = 11

The second way is longer but easier to explain...
Bigger number + smaller number = 15
Bigger number - smaller number = 7

So, bigger number + smaller number + bigger number - smaller number = 15 + 7 = 22

Which is the same as bigger number + bigger number = 22

So 1 of the bigger numbers is 22/2 = 11

Hope I helped!

To get the bigger number (big unit), do addition instead of subtraction.

15 + 7 = 22
22/2 = 11[/quote]I like using model in my solution as I think it's easy to see and the children will have confidence in model drawing when they go to upper primary.

B No [ ] [ 7 ] } Total 15
S No [ ]

So 15 - 7 = 8
2 units = 8
1 unit = 4
so small no is 4 and big no is 4 + 7 = 11

:celebrate:

Can we have some computer lessons on how to draw image and post? :please: DS3 has been calling me a computer idiot. :x