Q&A - PSLE Math

[Michaelia0816]

Thanks!

[Michaelia0816]

tianzhu:

Michaelia0816:

To Tianzhu, pls help with my math booklet HW last question,

OPQRS is part of a circle of radius 10cm. OPR and OQS are quarter circles. The area of the shaded part OQR is 40cm2, and the perimeter of the shaded part OQR is 28cm.

(Go to this web below for the picture of the figure)
http://t.co/4VZEguWj

For each following, use the calculator value of pi to find,
(a) the area of the figure OPQRS, correct to 2 decimal places,
(b) the perimeter of the figure OPQRS, correct to 2 decimal places

Hi

I believe you merely just wanted to confirm your answers.

They are 117.10 sq cm and 43.42cm.

Bye and have a nice weekend.

Best wishes

But can you still give me the solution, my answer not similar to your

[tianzhu]

Michaelia0816:

But can you still give me the solution, my answer not similar to your

Hi

Don’t worry too much about not having the same answers as me. My answers may not be correct.

To better illustrate the solution, it’s preferable to have some form of visual representation.

I’ll PM to you, hopefully, by tomorrow evening.

Best wishes

[jtparent]

tianzhu:

jtparent:

2. Tan, Lim and Wong had some pens to sell. Tan had the least number of pens. Wong's number of pens was 30% less then Lim. After Tan and Lim had each sold 50% of their pens, Lim had 95 more pens than Tan. If the 3 men had a total of 330 pens left, what was the total number of pens they had at first?

Hi

Lim ------- 10 units

Wong ------ 7 units

After Tan and Lim had each sold 50% of their pens,

Lim ------- 5 units

Tan ------- 5 units – 95

Wong ------- 7 units

17 units – 95 ------- 330

1 unit ------ 25

I’ll leave it to you to work out the rest of the details. The answer is 485.

Best wishes

Hi

may i know how u get the ans 485 cos my is 580

lim 10 u - 250
wong 7 u - 175
tan 250-95 =155

[Winx5015]

Good evening! I need help for the following questions.


Q1. The dimensions of a rectangular tank are 4m by 5m by 8m. If a cube, of side which is equal to one of the dimensions of the rectangular tank, is placed entirely within the rectangular tank, what is the ratio of the volume of the cube to the volume within the rectangular tank that is not occupied by the cube?
(1) 2:3
(2) 2:5
(3) 5:16
(4) 25:7

Q2). Ros has recipe for 8 chocolate cupcakes, each with a mass of 63g. To make the 8 cupcakes, she weighs two eggs and puts them in a bowl. She then adds in flour which weighs two times the mass of two eggs and sugar which weighs half the mass of two eggs. What was the mass of one egg she used, in grams?

Thanks

[Michaelia0816]

I’m okay with it, Tianzhu! Thanks!

[Michaelia0816]

May I knew the heuristic way to solve this kind of question,


There were 160 boys and 100 girls at the Christmas party. An equal number of boys and girls left the party before its ended. In the end, the number of boys at the party became thrice the number of girls. How many girls left the party?

[tianzhu]

jtparent:

Hi

may i know how u get the ans 485 cos my is 580

lim 10 u - 250
wong 7 u - 175
tan 250-95 =155

Hi

After Tan and Lim had each sold 50% of their pens, Lim had 95 more pens than Tan.

50% of Lim’s share is 95 more than Tan.

Hence, Tan’s number of pens@first -------250 – 95 – 95 ------ 60

Total number ------ 350 + 175 + 60 -------485

Best wishes

[tianzhu]

Winx5015:

Good evening! I need help for the following questions.


Q1. The dimensions of a rectangular tank are 4m by 5m by 8m. If a cube, of side which is equal to one of the dimensions of the rectangular tank, is placed entirely within the rectangular tank, what is the ratio of the volume of the cube to the volume within the rectangular tank that is not occupied by the cube?
(1) 2:3
(2) 2:5
(3) 5:16
(4) 25:7

Hi

The answer is (1).

Only a 4*4*4 cube can be placed entirely within the rectangular tank.

64:96 ------ 2:3

Best wishes

[tianzhu]

Winx5015:

Q2). Ros has recipe for 8 chocolate cupcakes, each with a mass of 63g. To make the 8 cupcakes, she weighs two eggs and puts them in a bowl. She then adds in flour which weighs two times the mass of two eggs and sugar which weighs half the mass of two eggs. What was the mass of one egg she used, in grams?

Hi

Sugar ----- 1 unit

Eggs ------- 2 units

Flour ------- 4 units

7 units ------- 504 (63*8)

1 unit ------ 72 (mass of 1 egg)

Best wishes