Tutor MathsGuru: Ask me for your burning Maths questions!

[Vanilla Cake]

Hi YLH88,

Hope this helps while waiting for Mathsguru's model solution.

YLH88:

1) Jane was thinking of a fraction. The sum of its numerator and denominator was 34. After I added 98 to its denominator, the fraction became 1/11. What was the fraction that Jane was thinking of ?

1/11 = 11/121
121-98 = 23
34-23=11
Fraction that Jane was thinking of was 11/23

YLH88:

2) Alex, Ben and David went for a run but none of them completed the run.Ben ran 5 times as far as Alex before he stopped.David stopped 1 km before the finishing line and he ran 3 km less than twice the distance Ben ran.The three of them ran 21 km, how long was the run ?

Alex - 1 unit
Ben - 5 units
David - 10 units - 3 km

1 unit + 5 units + 10 units - 3 km = 21 km
16 units = 24 km
1 unit - 1,5 km

Distance of the run was 10 units - 3km + 1 km
= 10(1.5)km - 3km + 1km
= 15 km-3 km+1 km
= 13 km

[Vanilla Cake]

Hi firebird,

Non-model solutions for your reference while waiting for Mathsguru's model solutions. Hope it may help you a little bit.

firebird:

1) The ratio of the number of pencils to the number of erasers in a box was 2:3. When 42 pencils were added and 15 erasers were removed, the ratio of the number of pencils to erasers became 3:4. How many erasers were there left in the box?

Before
P : E
2 : 3

Change
Add 42 pencils
Remove 15 erasers

After
P : E
3 : 4

Balance both sides based on information given by the question.
4(2 units+42) = 3(3 units-15)
8 units + 168 = 9 units-45
1 unit = 213

Number of erasers left in the box = 3 units-15
=3(213)-15
=624

firebird:

2) Container A has 150 more marbles than Container B. If 30 marbles are being transferred from Container B to Container A, there will be thrice as many marbles in Container A as Container B. How many marbles are there in Container A in the beginning?

Before
Container A -> unit + 150
Container B -> unit

Change
30 marbles transferred from Container B to Container A

After in terms of ratio
Container A : Container B
3 : 1

Equate both sides,
3(unit-30) = unit+150+30
3 units - 90 = unit + 180
2 units = 270
1 unit = 135

In the beginning, number of marbles in Container A is 135+150= 285

firebird:

3) There are some black and white marbles in a bag. If 20 black marbles are removed from the bag, the total number of marbles left will be 7 times the number of black marbles left.
If 50 white marbles are removed from the bag, the total number of marbles left will 5 times the number of black marbles left.
How many marbles are there in the bag?

Black - B
White - W

Case 1
7(B-20) = B-20+W
7B-140 = B-20+W
6B-W = 120 ------ (1)

Case 2
W-50+B = 5B
W-4B = 50 ------ (2)

(1)+(2)
2B = 170
B= 85
W=6B-120 = 6(85)-120 = 390

B+W = 85+390 = 475
Number of marbles in the bag is 475

Pls refer to http://prischoolmaths.blogspot.com/2009/09/acs-whole-number.html for better explanation.

[Vanilla Cake]

terzacice3:

1. A baker had some eggs. He used 1/7 of them on Monday and 1/11 of the rest on Tuesday. He bought another 153 eggs and then had as many eggs as he had at first. How many eggs did he have at first?


2. A rectangular board measures 630cm by 396 cm. It is divided into small squares of equal size.
a. (i) Find the largest possible length of the side of a square.
(ii) Find the least number of squares.

b. (i) Find the second largest possible length of the side of a square.
(ii) Find the number of squares in this case.

3. A box contains an assortment of 3 types of chocolate bars. It has 18 bars with almonds, 24 bars with hazlenuts and 30 bars with peanuts. The chocolate bars are shared among some students. Each student has only 1 type of chocolate bar and every student has the same number of chocolate bars. Suppose each student has the greatest number of chocolate bars.
a. How many chocolate bars does each student have.
b. How many students will have chocolate bars with peanuts.

4. A bag contained 100 marbles of 5 colors. There were 20 marbles of each of the colors. Without looking into the bag, what is the fewest number of marbles I must pick to be sure to get 5 marbles of the same color? Explain your answer.

Hi terzacice3,
Pls refer to this http://www.onsponge.com/forum/35-thinkingmathonsponge/1994-hcf-and-remainder-questions.html for the worked solutions. BTW, where are these questions from?

[CoffeeCat]

YLH88:

Hi Mathsguru,


Need your help with the below 2 questions :

1) Jane was thinking of a fraction. The sum of its numerator and denominator was 34. After I added 98 to its denominator, the fraction became 1/11. What was the fraction that Jane was thinking of ?
(ans given was : 11/23)

hey is this question a shortanswer question or a problem sum?

[Vanilla Cake]

CoffeeCat:

YLH88:

Hi Mathsguru,


Need your help with the below 2 questions :
1) Jane was thinking of a fraction. The sum of its numerator and denominator was 34. After I added 98 to its denominator, the fraction became 1/11. What was the fraction that Jane was thinking of ?
(ans given was : 11/23)

hey is this question a shortanswer question or a problem sum?

Hi CoffeeCat,
This Jane's fraction question is taken from Raffles Girls' Primary School SA1 2009 Paper 2 Q11. It's a 3-mark question and the paper was set on 12 May 2009.

[Vanilla Cake]

KSP:

I need help on the 2 questions below.


1. The figure below is not drawn to scale. Given that the area of WXYZ is 40cm sq, find the area of the shaded part. Ans: 68cm sq

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

2. The figure below is made up of two identical right-angled triangles, a small square and a big square. The parimeter of the shaded region is 50cm, and the total area of the two unshaded squares is 254.5cm sq. Find the total area of the two shaded right-angled triangles. Ans: 114.75cm sq

http://www.postimage.org/image.php?v=gxNVMm9

Hi CoffeeCat,
For your info.All these questions are also from the same paper - Raffles Girls' Primary School - P6 SA1 2009.

Q1 posted by KSP was from paper 2 Q13b. - 3 marks
Q2 posted by KSP was from paper 2 Q14 - 5 marks

KSP:

Hi mathsguru, I have the working for these 2 questions from Dharma but can you show me the model method to solve them? Thanks.

1. Container A contains 250 red marbles and 200 blue marbles. Container B contains 600 red marbles and 150 blue marbles. How many red and blue marbles must be moved from Container A to Container B such that 25% of the marbles in Container A are red and 75% of the marbles in Container B are red? Ans: 350

2. In a math competition, participants can obtain 4 possible award: Gold, Silver, Bronze and Participation. 3/7 of the participants obtained Gold awards, 1/4 of the them obtained Silver awards, and 1/6 of them obtained Bronze awards. Given that there were less than 100 participants taking the competition,
a) How many participants obtained the awards for Participation? Ans: 13
b) How many more participants obtained Gold awards then Bronze awards? Ans: 22

Posted by KSP
Q1 posted by KSP was from paper 2 Q18 - 5 marks
Q2 posted by KSP was from paper 2 Q16 - (a) 3 marks, (b) 2 marks

YLH88:

2) Alex, Ben and David went for a run but none of them completed the run.
Ben ran 5 times as far as Alex before he stopped.
David stopped 1 km before the finishing line and he ran 3 km less than twice the distance Ben ran.
The three of them ran 21 km, how long was the run ?
(ans given was 13 km)

Q2 posted by YLH88 was from paper 2 Q12 - 4 marks

[firebird]

Dear Vanilla cake


Good morning.

Many thanks.
firebird

[firebird]

Dear Mathsguru


Good afernoon.

Please help if you have access to the quesions mentioned bellow.

I am rather in an unusual position. The reason being I have problems with 2 questions that have diagrams as part of the question. Which I am unable to attach herewith as I do not have a scanner. All the these questions are from S’pore Hokkien Kuay Kuan, 2009, Primary 6, Paper 2, Preliminary Examination:

Question 11) In the figure below, not drawn to scale, PQRS is a rectangle with a length of 45 cm and a width of 22 cm. The area of te TUVW is 75 cm2. Find the ratio of the shaded area to the unshaded area.


Quesion 13) The figure below shows 2 squares, ABCD and EFGH, The length of each square is a whole number. The area of the unsaded part is 28 cm2. What is the perimeter of the square ABCD?

Question 15) A car and a coach travelled from Town A to Town B. The coach left town A at 0648 and it took 5 hours to reach Town B. The car started 30 minutes later than the coach and it took 4 hours to reach Town B. At what time did the car catch up with the coach?

Please help me if you have access to the question above.

Many thanks
firebird

[Vanilla Cake]

firebird:

Question 11) In the figure below, not drawn to scale, PQRS is a rectangle with a length of 45 cm and a width of 22 cm. The area of the TUVW is 75 cm2. Find the ratio of the shaded area to the unshaded area.

Pls refer to http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=280&postdays=0&postorder=asc&start=910 for the picture/discussion.

firebird:

Quesion 13) The figure below shows 2 squares, ABCD and EFGH, The length of each square is a whole number. The area of the unsaded part is 28 cm2. What is the perimeter of the square ABCD?

Here for the http://2.bp.blogspot.com/_NGNaLTzN5_U/SrTeN-wcr_I/AAAAAAAADxk/vGE3b_nsA08/s1600-h/Maths0609SA2P2HKAreanPerimeterQ13.JPG and here for the http://4.bp.blogspot.com/_NGNaLTzN5_U/SrTeVLi1BFI/AAAAAAAADxs/ebShQxrAQok/s1600-h/Maths0609SA2P2HKAreanPerimeterQ13A.JPG done by Uncle Observer.

firebird:

Question 15) A car and a coach travelled from Town A to Town B. The coach left town A at 0648 and it took 5 hours to reach Town B. The car started 30 minutes later than the coach and it took 4 hours to reach Town B. At what time did the car catch up with the coach?

Suggested http://3.bp.blogspot.com/_NGNaLTzN5_U/SrDgg0YtjtI/AAAAAAAADlk/Orf8PMPGSUs/s1600-h/Maths0609SA2P2HKSpeedQ15A.JPG by Uncle Observer.

firebird:

Please help me if you have access to the question above.

Access for the http://test-paper.info/filemgmt_data/files/P6%20Maths%20SA2%202009%20Hokkien%20Huay%20Kuan.pdf paper. You have to signup as a member to access to this file.Let's wait for Mathsguru's model solutions.

[mathsguru]

terzacice3:

:?: xD


Hi hope someone can help solve these few maths problem. I'm desperate as I'm lousy in maths.

1. A baker had some eggs. He used 1/7 of them on Monday and 1/11 of the rest on Tuesday. He bought another 153 eggs and then had as many eggs as he had at first. How many eggs did he have at first?

2. A rectangular board measures 630cm by 396 cm. It is divided into small squares of equal size.
a. (i) Find the largest possible length of the side of a square.
(ii) Find the least number of squares.

b. (i) Find the second largest possible length of the side of a square.
(ii) Find the number of squares in this case.


3. A box contains an assortment of 3 types of chocolate bars. It has 18 bars with almonds, 24 bars with hazlenuts and 30 bars with peanuts. The chocolate bars are shared among some students. Each student has only 1 type of chocolate bar and every student has the same number of chocolate bars. Suppose each student has the greatest number of chocolate bars.
a. How many chocolate bars does each student have.
b. How many students will have chocolate bars with peanuts.

4. A bag contained 100 marbles of 5 colors. There were 20 marbles of each of the colors. Without looking into the bag, what is the fewest number of marbles I must pick to be sure to get 5 marbles of the same color? Explain your answer

:?:

Hi Terzacice3,

Here're my solutions. Hope they are clear enough!


MathsGuru

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

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

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

http://www.postimage.org/image.php?v=aVtFIi0