Tutor MathsGuru: Ask me for your burning Maths questions!

[starlight1968sg]

Hi,

I need some help here:
Jane has 70 dresses than skirts. She sold 3/4 of the dresses and 3/5 of the skirts. She sold 126 more dresses than skirts. What fraction of the remaining clothes that Jane had were skirts?
Many thanks.

[Vanilla Cake]

starlight1968sg:

Hi,

I need some help here:
Jane has 70 dresses than skirts. She sold 3/4 of the dresses and 3/5 of the skirts. She sold 126 more dresses than skirts. What fraction of the remaining clothes that Jane had were skirts?
Many thanks.

Hi starlight1968sg,
Just curious, your question is from http://www.orlesson.org/orp/09Ma/2009-Math-SA2-SCGS.pdf.It's a 5-mark question and you changed the original name - Zara to Jane. Why?

Before
Dresses : 4u
Skirts: 4u-70

Sold
Dresses: 3u
Skirts: 3/5x(4u-70)= 2.4u-42

Sold 126 more dresses than skirts-> 3u=2.4u-42+126
0.6u=84
u = 140

After
Dresses: 1u = 140
Skirts: 4u-70-(2.4u-42) = 4u-70-2.4u+42 = 1.6u-28 = 1.6(140)-28=224-28=196

196/(140+196)=196/336 = 7/12

Fraction of the remaining clothes that Jane had were skirts = 7/12.

Hope that other members will come with model drawing solutions and other alternatives.

[firebird]

Dear maths guru


Good evening.

Please help me on the following maths which I am assisting my child:

1) Mdm Ang bought some highlighters, pens and mechanical pencils. 1/4 of them were highlighters. The number of pens she bought was 6 more than 1/2 of the total number of all items and the remaining were mechanical pencils. Each of the highlighters, pens and mechanical pencils cost $2.10, $4.05 and $1.60 respectively. She spent a total of $227.10 on all items. How many pens did she buy altogether?

This is Nanyang Primary SA 2 2009 question 18.

2) Simple sum but I want to check with you

What is the sum of all the common factors of 12, 18 and 24?

12 - 1,2,3,4,6,12 = sum of all = 28
18 - 1,2,3,6,9,18 = sum of all = 39
24 - 1,2,3,4,6,12,24 = sum of all = 60

So sum all three above = 28+39+60= 127

Kindly correct me.

Thank you.
With best regards
Firebird

[Vanilla Cake]

firebird:

1) Mdm Ang bought some highlighters, pens and mechanical pencils. 1/4 of them were highlighters. The number of pens she bought was 6 more than 1/2 of the total number of all items and the remaining were mechanical pencils. Each of the highlighters, pens and mechanical pencils cost $2.10, $4.05 and $1.60 respectively. She spent a total of $227.10 on all items. How many pens did she buy altogether?

Pls refer to http://www.onsponge.com/forum/35-thinkingmathonsponge/2485-p6-maths.html#2487, http://4.bp.blogspot.com/_NGNaLTzN5_U/SrxEa7u6fKI/AAAAAAAAD18/ogX5J0DWc5Q/s1600-h/Maths0609SA2P2NYFractionQ18A.JPG and http://www.onsponge.com/index.php?option=com_kunena&Itemid=282&func=view&id=3881&catid=35#3881 while waiting for Mathsguru's reply.

firebird:

2)What is the sum of all the common factors of 12, 18 and 24?

Factors of 12 -> 1,2,3,4,6,12
Factors of 18 -> 1,2,3,6,9,18
Factors of 24 -> 1,2,3,4,6,12,24

Common factors of 12, 18, 24 -> 1,2,3,6
Sum of all the common factors of 12, 18 and 24 = 1+2+3+6 = 12

Hi Firebird,
Have you bought the newly released set of 2010 P6 Prelim Maths papers from top schools for your child to practise?
Wish your child all the best in his/her PSLE 2010 exams.

[Dharma]

firebird:

Dear maths guru


Good evening.

Please help me on the following maths which I am assisting my child:

1) Mdm Ang bought some highlighters, pens and mechanical pencils. 1/4 of them were highlighters. The number of pens she bought was 6 more than 1/2 of the total number of all items and the remaining were mechanical pencils. Each of the highlighters, pens and mechanical pencils cost $2.10, $4.05 and $1.60 respectively. She spent a total of $227.10 on all items. How many pens did she buy altogether?

This is Nanyang Primary SA 2 2009 question 18.

Hi Firebird,


Highlighters => 1u
Pens => 2u + 6
Mechanical pencils => 4u – 1u – (2u + 6) = 1u – 6

1u($2.10) + (2u + 6)($4.05) + (1u – 6)($1.60) = 11.8u + $14.70

11.8u + $14.70 = $227.10
11.8u = $ 227.10 - $14.70 = $212.40
1u = 18

No. of pens bought = 2u + 6 = 2(18 ) + 6 = 42

firebird:

2) Simple sum but I want to check with you

What is the sum of all the common factors of 12, 18 and 24?

12 - 1,2,3,4,6,12 = sum of all = 28
18 - 1,2,3,6,9,18 = sum of all = 39
24 - 1,2,3,4,6,12,24 = sum of all = 60

So sum all three above = 28+39+60= 127

Kindly correct me.

Thank you.
With best regards
Firebird

You had worked out all the factors of 12, 18 and 24 and summed them up. The question requires us to find the sum of the COMMON FACTORS of 12, 18 and 24.

Common factors of 12, 18 & 24 = 1, 2, 3 , 6
Sum = 1 + 2 + 3 + 6 = 12

[Dharma]

starlight1968sg:

Hi,

I need some help here:
Jane has 70 dresses than skirts. She sold 3/4 of the dresses and 3/5 of the skirts. She sold 126 more dresses than skirts. What fraction of the remaining clothes that Jane had were skirts?
Many thanks.

4u – 5p = 70 --------------- ( 1 )
3u – 3p = 126 -------------- ( 2 )
5u – 5p = 210 --------------( 2) x 5/3 = (3)

(3 ) – (1)

1u = 140
1p = 140 – 42 = 98

Remaining clothes = 1u + 2p = 140 + 2( 98 ) = 336
Fraction of skirts = 2(98 )/ 336 = 7/12

[firebird]

Dear Vanilla Cake


A very good morning to you.

Your reference and solution is very clear.

I am going to call Mr. Jeremy at 90216478 for the 2010 P6 Prelim papers. Could you kindly recommend any other source or specific shop? Hope not asking you too much!

Many thanks for your best wishes for my son’s PSLE 2010 exams.

With best regards
Firebird

[firebird]

Dear Dharma


Good morning.

Your solutions are very good.

I am extremely greatful for pointing "sum of all COMMON factors" and not "sum of ALL factors". I have given my child the wrong solutuion.

Many thanks

With best regards
Firebird

[Vanilla Cake]

firebird:

Your reference and solution is very clear.

Dear firebird,

A very good morning to you too,
My younger sister (P5) will be taking PSLE 2011, so our family is very worried for her. That's why I have to keep track of the current P6/PSLE Maths questions and know the current trend that the P6 student must know how to answer correctly. I hope that someone like Uncle Dharma or Uncle Tianzhu may wish to create a blog to provide P6 Maths solutions for past years' questions from top schools like 2010, 2009 and so on. Just only the 18 questions in the paper 2 will be sufficient. Maybe, KSP Chief may consider creating a section in this forum whereby P6 Maths detailed solutions are worked out by resident Maths solvers like Uncle Dharma/Uncle Tianzhu in KSP forum categorised by school and level. This will allow anyone to refer to them for reference instead of duplicating and posting the same questions again and again in the Maths thread.

firebird:

I am going to call Mr. Jeremy at 90216478 for the 2010 P6 Prelim papers. Could you kindly recommend any other source or specific shop? Hope not asking you too much!

From KSP forum-http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=4105, these are the possible places for selling top papers:

1. Bras Basah Complex - a number of shops are selling.
2. Near Hougang plaza - Blk 804 (not 100% sure), ground floor
3. Near Kovan MRT station - near DBS bank
4. Toa Payoh Central, next to KFC, near MRT, near an Indian Bank, at the corner.
5. Two stalls selling these papers in Thomson Plaza.
6. Tampines Mart - Sam 93397910.
7. Bukit Merah Centre (Outside NTUC)
8. Peace Center
9. Marine Parade

You are always welcome. Hope that my help is useful to you in one way or another.

[sally72]

Hi,

Just bought the 2010 Prelim P6 from Marine Parade.
The stall Aunty said : \" Fast Fast take, no more in my boss's van liao!\"

:lol: KSP