Q&A - PSLE Math

[Neat]

Hi


Please help with these 2 questions:

1. Susan has some vanilla and chocolate sweets in her bag. If she adds 20 vanilla sweets into the bag, the percentage of vanilla sweets in the bag becomes 40%. If she adds 30 chocolate sweets, there will be 70% of chocolate sweets in the bag. How many vanilla and chocolate sweets does she have?

2. Mr Samad made some toys to sell. He sold 20% of the toys on Monday. He sold 27 toys on Tuesday. On Wednesday he sold 10% of the remaining toys. After that he found that the toys he had left was 1 more than 1/2 the number of toys he had made. How many toys did he made?

Thank You.

[MathIzzzFun]

Neat:

Hi


Please help with these 2 questions:

1. Susan has some vanilla and chocolate sweets in her bag. If she adds 20 vanilla sweets into the bag, the percentage of vanilla sweets in the bag becomes 40%. If she adds 30 chocolate sweets, there will be 70% of chocolate sweets in the bag. How many vanilla and chocolate sweets does she have?

Thank You.

Hi

Q1
if 20 vanilla sweets added,
Vanilla : Chocolate = 40: 60 --> 2u : 3u
total Vanilla : Chocolate --> 2u - 20 : 3u

If 30 chocolate added,
Vanilla : Chocolate --> 2u-20 : 3u+30 = 3:7

cross multiply/equalize,
14u - 140 = 9u+90, 1u--> 46

Vanilla --> 2x46 - 20 = 92
Chocolate --> 3 x 46 = 138

cheers.

[MathIzzzFun]

Neat:

Hi


Please help with these 2 questions:


2. Mr Samad made some toys to sell. He sold 20% of the toys on Monday. He sold 27 toys on Tuesday. On Wednesday he sold 10% of the remaining toys. After that he found that the toys he had left was 1 more than 1/2 the number of toys he had made. How many toys did he made?

Thank You.

Hi

Could you check the source of the question, while the answer is a whole number (115), it does not make sense because (1/2 of 115 + 1) is not a whole number.

cheers.

[yapperz2000]

speedmaths.com:

yapperz2000:

http://i50.tinypic.com/302t8ol.jpg\">

I need help with this question.
Couldn't find the answers as it is catholic high prelims 2008 maths.
Thanks!

Hi,

This is a \"Difference between Two Square Numbers\" type of question.

List out the first few square numbers:
1, 4, 9, 16, 25, 36, 49, ...

The difference between which 2 square numbers = 32?

Can you work from here?

Cheers


speedmaths.com


.

Using algebra, i got 7...

[Michaelia0816]

Tianzhu, need help with my homework, cannot understand why I cannot get the right answer* :?:


*some question only, question with * is needed help with

1)A survey was conducted to find out the number of the number of pupils who had digital watches and the number of digital watched they had. The pie chart ....( I think the rest of the part of the question is not important so I ...)

(Group A)Number of digital watches ---> 0
(Group B)Number of digital watches ---> 1
(Group C)Number of digital watches ---> 2
(Group D)Number of digital watches ---> More than 2

Group A got 80 people.
Group B got 90 people.
Group C got 20 people.
Group D got 5 people.

* How many pupils had more than 1 digital watch?
( Is it answer 115 or 25?)

Another question.....

*2) What is the maximum number of circles of radius 7cm that can be cut from a vanguard sheet, 32cm by 30cm? ( Take pi as 22/7)
1) 3
2) 4
3) 6
4) 16

[Michaelia0816]

Help me with this question,

1)Aminah put 19 candies in Bag A,24 candies in Bag B,15 candies in Bag C and 80 candies in Bag D.She then added an equal number of candies into each of the bags.As a result Bag,D contained the same number of candies as the total number of candies in bags A,B and C.How many candies were there in Bag D at the end?

I know the answer is 91. But the solution, one of the part I do not understand,

Candies A + candies B + candies C —> 19 + 24 + 15 = 58

Candies D —> 80

Difference [D - (A + B +C)] = [80 - 58] = 22

let ‘1u’ be the equal no. of candies were added to each bag.

(A + B + C)… : (D)
1u + 1u + 1u : 1u

Difference (3u - 1u) = 2u

2u —> 22
1u —> 11

In the end, candies in D —> 80 + 11 = 91

Provided by Simon Teh, onsponge.

How to get 3u and 1u?

[tianzhu]

Hi


Q1) 20 + 5 ------ 25

Q2) 4 number of circles

Best wishes

[tianzhu]

Michaelia0816:

How to get 3u and 1u?

Hi

She then added an equal number of candies into each of the bags.

If the number added is 1u, we’ll have 1u for every one of the bags.

A – 1u

B – 1u

C – 1u

D – 1u

As a result Bag,D contained the same number of candies as the total number of candies in bags A,B and C.

80 + 1u ------- (19+1u) + (24+1u) + (15+1u)

You may carry on from here.

Best wishes

[dicoyote]

Hi,


Need some help on this question, thanks

Ali and Faiz had 576 sticks of satay altogether. Ali had 58 more sticks than Faiz. When Faiz had sold 1/3 as many sticks of satay as Ali, he was left with twice as many sticks as Ali. How many sticks of satay did Faiz sell?

[Michaelia0816]

Tianzhu, pls help with this question, it is from the CBS paper.


1) http://t.co/Xw6EKArf

2) http://t.co/DhdNHZqU ( read the caption)

3) http://t.co/e3zH6LZq