Q&A - P5 Math

[MathIzzzFun]

imacsg:

Can someone help?

Mark's current age is 1/4 of Ronald's. In 24 years' time, Ronald's age will be 14 years less than twice Mark's age. What is Ronald's age now?

Thanks,

Hi
Now:
Mark's age --> 1 unit
Ronald's age --> 4 units

24 years' time:
Ronald's age --> 4 units + 24
Mark's age --> 1 unit + 24
4 units + 24 = 2 units + 48 - 14
1 unit --> 5

Ronald's age now --> 20

cheers.

[mathnoobs]

Zack7:

* i have to say these questions are quite tricky, harder than the questions i see at the p6 section

yes, pity our poor children.... so little time for play now....it's just mug, mug, mug...

[tianzhu]

mummyv:

2. There are 9 stack of chairs. There are 12 chairs in each stack. Mohan places each chair equally spaced apart to for a perimeter of a rectangle. If the number of chairs places along the length is thrice the number of chairs placed along the breadth, how many chairs are placed along one of the lenghts of the rectangle. (Ans 42)

Hi

Good Morning.

Perhaps, for questions of such genre, it’s useful to have a simple pictorial representation. It might help to organise your thoughts.

Hope this helps.

Best wishes

http://farm6.staticflickr.com/5272/6897367566_8d8cd99d93_z.jpg\">

[mummyv]

MathIzzzFun:

mummyv:

Hello


It's time from SA2 prep & Would appreciate some help solving the following questions 1b and 2

1. Ms Tan bought 4 times as many toy guns as teddy bears. She spent $1750 altogether. A toy gun cost $10 less than a teddy bear. Total cost of toy guns was $490 more than total cost of teddy bears.
a. How much did Ms Tan spend on teddy bears (Ans$630)
b. How much did one teddy bear cost (Ans $18)

2. There are 9 stack of chairs. There are 12 chairs in each stack. Mohan places each chair equally spaced apart to for a perimeter of a rectangle. If the number of chairs places along the length is thrice the number of chairs placed along the breadth, how many chairs are placed along one of the lenghts of the rectangle. (Ans 42)

Thanks in advance all the maths gurus

Hi
Q1.
Amount spent on teddy bears --> $(1750-490)/2 = $630
Amount spent on toy guns --> $1750 - $630 = $1120
Ms Tan bought 4 times as many toy guns as teddy bears
--> 4 groups of toy guns, 1 group of teddy bear
1 group of toy guns --> $ 1120/4 = $280
$630-$280= $350 --> 1 group of teddy bears cost $350 more than 1 group of toy guns
Number of teddy bears/toy guns in 1 group --> $350/$10 = 35
Cost of 1 teddy bear = $630/35= $18

Q2.
You may want to draw a rectangle with 9 beads on each length and 3 beads on each breadth (total 20 beads), when the number of beads on 1 length and 1 breadth are added, we add 2 more beads to 1/2 the total number ie 9+3=12 = 10 + 2.

Total number of chairs --> 12 x 9 = 108
Length + breadth --> 4 units --> (108/2) + 2
1 unit --> 56 / 4 = 14
Length --> 3 units --> 3 x 14 = 42 chairs.

cheers.

Thanks MathIzzzFun :salute: you are really good at maths

[mummyv]

Zack7:

mummyv:

Hello


It's time from SA2 prep & Would appreciate some help solving the following questions 1b and 2

1. Ms Tan bought 4 times as many toy guns as teddy bears. She spent $1750 altogether. A toy gun cost $10 less than a teddy bear. Total cost of toy guns was $490 more than total cost of teddy bears.
a. How much did Ms Tan spend on teddy bears (Ans$630)
b. How much did one teddy bear cost (Ans $18)

2. There are 9 stack of chairs. There are 12 chairs in each stack. Mohan places each chair equally spaced apart to for a perimeter of a rectangle. If the number of chairs places along the length is thrice the number of chairs placed along the breadth, how many chairs are placed along one of the lenghts of the rectangle. (Ans 42)

Thanks in advance all the maths gurus

let x be number of teddy bear, no of guns = 4x
let y be cost of each teddy bear, cost of gun = y-10

so

4x(y-10) + xy = 1750 --- eq1
4x(y-10) - xy = 490 --- eq2

eq1 - eq2

2xy = 1260
xy = 630 (cost of bears)

cost of guns = 1750 - 630 = 1120 = 4x(y-10)

so sub x = 630/y into the above

so

1120 = 4(630/y) (y-10)
y = 18 bucks... thats pretty expensive.



question 2

this is a perimeter question

let breathe be x
length = 3x

perimeter = 8x

9 x 12 = 108

but notice that based on the way we formalise the answer, i.e we let breathe be x, length be 3x,

if the perimeter is 8x, then we would have double counted the 4 corners. i.e, our 4 corner chairs can act as both the length and the breadth.

so the total chairs is 9 x 12 + 4 = 112.

so 8x = 112, x = 14, length = 3x = 42.



* i have to say these questions are quite tricky, harder than the questions i see at the p6 section

Thanks Zack7. I myself got a shock at the questions. Every year I have to work harder to solve questions. Not easy being a kid and not easy trying to be a responsible, supportive mother.

[mummyv]

tianzhu:

mummyv:

2. There are 9 stack of chairs. There are 12 chairs in each stack. Mohan places each chair equally spaced apart to for a perimeter of a rectangle. If the number of chairs places along the length is thrice the number of chairs placed along the breadth, how many chairs are placed along one of the lenghts of the rectangle. (Ans 42)

Hi

Good Morning.

Perhaps, for questions of such genre, it’s useful to have a simple pictorial representation. It might help to organise your thoughts.

Hope this helps.

Best wishes

http://farm6.staticflickr.com/5272/6897367566_8d8cd99d93_z.jpg\">

Thanks tianzhu. I hope I can reach your level sometime this year

[Zack7]

mathnoobs:

Zack7:

* i have to say these questions are quite tricky, harder than the questions i see at the p6 section

yes, pity our poor children.... so little time for play now....it's just mug, mug, mug...

problems of a country that strives too hard for excellence

[YumYum]

Hi, can anyone pls help with this Qn:


Kate baked some chocolate, oatmeal, and sultana cookies.

The ratio of the number of chocolate cookies to the number of oatmeal cookies to the number of sultana cookies is 12:7:10.

She wanted to pack some cookies in a box for her neighbor.

If she packed only the chocolate and oatmeal cookies in the box, she would have 20 such cookies left.

If she packed only the oatmeal and sultana cookies in the box, she would have 12 such cookies left.

A) how many cookies could the box contain?
B) how many cookies did she bake?

Thanks!

[YumYum]

Hi, I need help with this Qn:


2/9 of the students in a school scored an ‘A’ for a test.

The number of students who scored a ‘B’ was 1 2/3 (one and two thirds) the number of students who scored an ‘A’.

The rest of the students scored a ‘C’ and a ‘D’ in the ratio 6:5.

The number of students who scored an ‘A’ was 100 fewer than the number of students who scored a ‘B’.

A) how many students were there in the school?
B) how many more students scored a ‘B’ than a ‘D’?

Thanks!

[tianzhu]

YumYum:

Hi, can anyone pls help with this Qn:


Kate baked some chocolate, oatmeal, and sultana cookies.

The ratio of the number of chocolate cookies to the number of oatmeal cookies to the number of sultana cookies is 12:7:10.

She wanted to pack some cookies in a box for her neighbor.

If she packed only the chocolate and oatmeal cookies in the box, she would have 20 such cookies left.

If she packed only the oatmeal and sultana cookies in the box, she would have 12 such cookies left.

A) how many cookies could the box contain?
B) how many cookies did she bake?

Thanks!

Hi

chocolate cookies: oatmeal cookies: sultana cookies ----- 12:7:10.

12units + 7 units – 20

7 units + 10 units – 12

19 units – 20 = 17 units – 12
2 units = 8
1 unit = 4

The box can contain (17*4) – 12 or 56 cookies

Number of cookies ------- 29*4 -------116

You may also use Systematic Listing as an alternate way.

Best wishes