Tutor MathsGuru: Ask me for your burning Maths questions!

[Vanilla Cake]

YLH88:

[quote]YLH88 wrote:

1) In the figure below, which is not drawn to scale, 1/5 of the circle is shaded. The ratio of the area of the square to the sum of area of the rectangle and the circle is 1 : 2. 60% of the square is shaded. 1/3 of the rectangle is shaded. What is the ratio of the area of the circle to the square to the rectangle ?
Vanilla Cake wrote :
Area of square : Area of rectangle+Area of circle
1 : 2
10 : 20

Hi Vanilla Cake,
May I know why you change the ratio for area of square : area of Rectangle + Area of circle from 1 : 2 to 10 : 20 ?[/quote]Hi YLH88,
I am VC's mum and VC won't be back home today until 7 pm plus due to SMO training and dance practice.
Sorry for the inconvenience caused due to VC's inadequate explanation as she is still a Sec 2 girl.

Area of square : Area of rectangle+Area of circle
1 : 2
Multiply by 10
10 : 20

because 60% of the square is shaded.60% = 3/5.
Instead of 1x 3/5 which will be inconvenient as 3/5 unit, expand the ratio by multiplying by 10. So, 10x3/5 = 6 units which is easier to calculate.

Hope this helps.
Submitted by VC's mum

[kitty2]

Vanilla Cake:

kitty2:

1)Audrey and Belle have some money each.If Audrey spends $18 and Belle spends $24 each day.Audrey will have $25 left.when belle has spent all her money.If Audrey spends $13 and belle spends $30 each day,Audrey will still have $139 left.when Belle has spent all her money.How much money do they have altogether?


2)Figure No of cakes

1 1
2 4
3 10

a)How many cubes will ther be in Fig 6?
b)Which figure will have 120 cubes?

Hi kitty2,
Pls refer to the links below while waiting for Mathsguru's solutions:

http://psle2010a.blogspot.com/2010/03/14.html
http://psle2010a.blogspot.com/2010/03/mathsp62009sa1p2ny.html
http://www.onsponge.com/forum/35-thinkingmathonsponge/2528-p6-maths.html
http://www.onsponge.com/forum/35-thinkingmathonsponge/1917-p6-maths-2009-nanyang-sa1-paper-2.html

Submitted by VC's mum.

:thankyou:

[i-mum]

Hi MathsGuru,


1. A, B & C shared some sweets. A received 1/11 of the sweets. B received 1/4 of the number of sweets C received. When C gave away 104 sweets to be shared between A and B, they found that all of them had the same number of sweets. How many sweets were there at first?

2. A, B and C shared a sum of money.
A’s share was 1 1/2 timess that of B and B’s share was 1 1/4 times that of C.
(a) what fraction of A’s share was C?
(b) If A gave B $19 and C $22, A would have as much money as C. Find the sum of money shared.

Thank You.

i-mum

[Dharma]

i-mum:

Hi MathsGuru,


1. A, B & C shared some sweets. A received 1/11 of the sweets. B received 1/4 of the number of sweets C received. When C gave away 104 sweets to be shared between A and B, they found that all of them had the same number of sweets. How many sweets were there at first?


i-mum

Q1)
A & B : 3u + 104 = 2p

C : 8u – 104 =1p

16u - 208 = 3u + 104
13u = 312
1u = 24

Total no. of sweets at first = 24 x 11 = 264


Q2)
A: 15u
B: 10u
8u

(a)\tFraction = 8/15b)\t

A : 15u - $41 = 1p
C : 8u + $22 = 1p

(b)
15u - $41 =8u + $22
7u = $63
1u = $9

Sum of money shared = 15u + 10u + 8u = 33u = 33 x $9 = $297

[Vanilla Cake]

i-mum:

1. A, B & C shared some sweets. A received 1/11 of the sweets. B received 1/4 of the number of sweets C received. When C gave away 104 sweets to be shared between A and B, they found that all of them had the same number of sweets. How many sweets were there at first?

Hi i-mum,

For the reference of readers in this forum, your Q1 was from Nanyang Primary School P5 SA1 2009 Paper 2 Q18 [5 marks] set on 15 May 2009.
A stands for Aifang, B stands for Bala and C stands for Cindy in Q1.

You may wish to refer to these links for the solutions while awaiting Mathsguru's reply.Thanks
http://www.onsponge.com/forum/35-thinkingmathonsponge/2529-nanyang-maths-sa1-2009-paper-2-q-18.html
http://www.onsponge.com/forum/35-thinkingmathonsponge/2638-p5-math.html

Submitted by VC's mum

[happies]

Hello Mathsguru,


Q1) A man is 45 years old when his son is t years old. How old is the man when his son is 15 years old?

Q2) 3/5 of May’s mass is 3/4 of June’s mass. If June’s mass is 52 kg, what is their total mass?

Q3) A number when divided by 6 gives a remainder of 1 and gives a remainder of 2 when divided by 5. What is the number?

Q4) I am a 4-digit number. All my digits are different. My first digit is 1/6 of my last digit. My second digit is 1/4 of my third digit. What number am I?

Thank you.

[happies]

happies:

Hello Mathsguru,


Q1) A man is 45 years old when his son is t years old. How old is the man when his son is 15 years old?

Q2) 3/5 of May's mass is 3/4 of June's mass. If June's mass is 52 kg, what is their total mass?

Q3) A number when divided by 6 gives a remainder of 1 and gives a remainder of 2 when divided by 5. What is the number?

Q4) I am a 4-digit number. All my digits are different. My first digit is 1/6 of my last digit. My second digit is 1/4 of my third digit. What number am I?

Thank you.

Oops, pls ignore Q1 & Q4 questions:))

[YLH88]

[quote]Hi YLH88,

I am VC's mum and VC won't be back home today until 7 pm plus due to SMO training and dance practice.
Sorry for the inconvenience caused due to VC's inadequate explanation as she is still a Sec 2 girl.

Area of square : Area of rectangle+Area of circle
1 : 2
Multiply by 10
10 : 20

because 60% of the square is shaded.60% = 3/5.
Instead of 1x 3/5 which will be inconvenient as 3/5 unit, expand the ratio by multiplying by 10. So, 10x3/5 = 6 units which is easier to calculate.

Hope this helps.
Submitted by VC's mum[/quote]Hi VC's mum,

No worries, there is no need to apologies, really. In fact, I'm very very grateful for all the help the she, mathsguru and all other parents have given in this forum. Greatly appreciated!

Sorry, i'm still abit blur in this question. Is it possible to multiple by 5 instead of 10 ? ie 5 x 3/5 = 3 ?

Thank you.

[i-mum]

Thanks Vanilla Cake and Dharma.


But for Q2, the answers was given by the school as 49 1/2 and $330. This paper was set before the ratio is taught and teacher did not give any solutions due to limited time :?

i-mum

[tisha]

CoffeeCat:

tisha:

Is it possible to solve these without algebra? These are P5 Questions from past year exam papers for SA1.

I believe algebra is only taught in P6, so just curious how come these questions can be asked for SA1 of P5 :?

Ken and Patrick had $625 at first. After buying some books, the amount of money Ken has left is 4 times the amount of money he spent and the amount of money Patrick has left is 5 times the amount of money he spent. Find the amount of money Patrick had at first if they have a total of $510 left.


There are 85 plates of chicken rice for 80 people. Each adult eats 2 plates of chicken rice and every 3 children share 1 plate of chicken rice. Find the number of adults and children respectively.

For qns 2. One common non-algebra way to solve such algebraical questions is to use this heuristic called \"make an assumption\".
First assume there are 80 adults. Then these 80 adults will eat 160 plates of rice.
Now we must try to find the number of children.
Notice that if we interchange 3 adults for 3 children, there will be a decrease in (2*3 -1) = 5 plates of rice from the total.
(if you are not convinced you can try 77 adults, 75 adults to see the pattern)
For every group of interchange of 3 adults for 3 children, we are 5 plates nearer the true total of 85. therefore, the number of children is 3*(160-85)*5 =45.

Thank you very much coffeecat for the non algebric solution.
But I'm not so clear on this part
For every group of interchange of 3 adults for 3 children, we are 5 plates nearer the true total of 85. therefore, the number of children is 3*(160-85)*5 =45
I suppose it is a typo and should be 3*(160-85)/5, but I still don't understand it. Sorry to bother you so much.