Q&A - PSLE Math

[Brenda10]

tianzhu:

Hi elkniwt and Brenda10.


Thank you for your wonderfull words.I am glad you liked them.

I’ve benefitted much learning from many other members in KSP. It opens my mind to many alternatives in problem solving.

If time permits, I’ll be happy to share some of my solutions, especially those relevant for Primary Maths.

Best wishes

Hi Tianzhu


We really appreciate all these wonderful illustration and valuable time you spent on helping us.

Now we are working on SA2 papers and may trouble you again. Thank you in advance.

[tianzhu]

Brenda10:

Now we are working on SA2 papers and may trouble you again. Thank you in advance.

Hi Brenda10

Thank you for having such faith in my Maths abilities
.
While I am flattered, I must say some questions may be beyond my knowledge and I may not be able to solve them.

Please feel free to post any questions (PSLE Maths) you may have, I am confident you’ll get relevant solutions as there are many other members helping to answer them.

If time permits, I’ll be glad to share some of my solutions.

Enjoy the PSLE journey with your girl.

Best wishes

[Brenda10]

Hi Tianzhu


Sure. This forum really has a lot of resourceful/helpful members that provide help to solve our headache.

BTW, is question on “speed” very difficult as I can see quite a numbers of question recently posted are related to this topics.

Thank you.

[kitty2]

elkniwt:

Hi Tianzhu,


I really like your illustrations and pictures. Very nice.

Regards.

:goodpost: yes i agree,thanks for your effort and time.

[Maths Monster]

kitty2:

Please kindly help with these questions, :thankyou:


1)Minli has 32 English & Chinese books.4/5 of the English books & 3/4 of the chinese books are fiction books.She has a total of 25 fiction books.How many english fiction books are there?

Let 5u be number of English book
English = 5u
Chinese = 32 - 5u

Friction books:
English Friction books = 4u
Chinese Friction books = 3/4 x (32 - 5u)

Since there are total of 25 fiction books, we can write:
4u + 3/4 x (32 - 5u) = 25
4u + 24 - 15/4u = 25
16u - 15u = 4
u = 4

Therefore,
Number of English books = 5u = 5 x 4 = 20
Number of English friction books = 4u = 16

Check:
Number of Chinese books = 32 - 5u = 12
Number of Chinese friction books = 3/4 x (32 - 5u) = 9

Total books = 20 + 12 = 32
Total friction books = 16 + 9 = 25

[Maths Monster]

kitty2:

Please kindly help with these questions, :thankyou:


2)Mr Miki had some track shoes in his shop.3/7 of them were Brand x,1/4 of the remainder were brand Y and the rest were brand Z


Types of shoes Amt earn/pair

Brand x $8
Brand Y $6
Brand Z $10

The table shows the amt he earn per pair of shoes.The number of brand X shoes sold to the number of Brand Y shoes sold to the number of brand Z shoes sold was 1:2:4.In total,he sold 1/5 of the shoes and earn $840.How many pairs of Brand Z shoes did he have at first?

Ratio of number of shoes sold
X : Y : Z
1 : 2 : 4

Ratio of amount shoes sold
$X : $Y : $Z
8x1 : 6x2 : 10x4
8 : 12 : 40

8 + 12 + 40 parts => 840
1 parts => 14

Amount of shoes sold
$X : $Y : $Z
$112 : $168 : $560

Number of shoes sold
X : Y : Z
14 : 28 : 56

Total shoes sold = 14 + 28 + 56 = 98
Total shoes at first = 98 x 5 = 490

Ratio of shoes at first:
X : Y + Z
3 : 4

Y : Z
1 : 3

X : Y : Z
3 : 1 : 3

3 + 1 + 3 parts => 490
1 part => 70
3 parts => 210

Therefore, he has 210 Brand Z shoes at first.

Check:
Total shoes = 490
Total shoes sold = 98
X shoes sold = 14 => 14 x $8 = $112
Y shoes sold = 28 => 28 x $6 = $168
Z shoes sold = 56 => 56 x $10 = $560
Total amount = $840

[Maths Monster]

kitty2:

Please kindly help with these questions, :thankyou:


3)A car & a lorry were heading from Town A to Town B.When the car overtook the lorry,they were 375km away from town B.The car arrived 1h15 min earlier than the lorry which was still 75km away from town B.

a) Find the average speed of the lorry
b) Find the average speed of the car

When car reached Town B, Lorry is 75km away and will take 1h15min to reach Town B.

a) Lorry speed = 75 / 1.25 = 60km/h

Time taken by Lorry from where Car overtook Lorry to Town B = D / S
= 375 / 60 = 6.25h

Time taken by car = 6.25 - 1.25 = 5hr

b) Car speed = D / T = 375 / 5 = 75km/h

[Maths Monster]

kitty2:

Please kindly help with these questions, :thankyou:


4)Siti had some red & blue marbles.80% of the marbles were red.After she bought another 63 red marbles & 46 blue marbles,75% of the marbles were red.Find the total number of marbles she had at first.

Let 10u be the total number of marbles

Before:
Red [8u]
Blue [2u]

After:
Red [8u+63]
Blue [2u+46]
If 75% of the marbles were red, we can write,
8u + 63 = 3 x (2u + 46)
8u + 63 = 6u + 138
2u = 75
u = 37.5

Therefore, total number of marbles at first = 10u = 375

Check:
Before:
Red = 0.8 x 375 = 300
Blue = 0.2 x 375 = 75

After:
Red = 300 + 63 = 363
Blue = 75 + 46 = 121
Total = 484
% of Red = 363/484 x 100% = 75%

[tianzhu]

kitty2:

:goodpost: yes i agree,thanks for your effort and time.

Hi kitty2

You’re welcome.

Best wishes

[ksmama]

Ann is driving to a destination. If she travels at 80km/h, she would be 20min late. If she travels at 60km/h, she would be 45 min late. How long will journey take if she travels at 90km/h.


For your help. Thnx!