Q&A - PSLE Math

[PapayaDad]

lee tong fong:

Hi, can anyone help me with another question


(4) Shaun and Chin Hong cycled along the same route from Point A to Point B
Shuan Cycled at the average speed of 20km/h and he was 4.5km ahead of Chin Hong when Chin Hong reached the half-way mark.
If Shuan reached Point B at 11:20am, what time would Chin Hong reach Point B?

Thanks you again

Shaun was 4.5km ahead of Chin Hong when Chin Hong reached the half-way mark.

So when Chin Hong reach Point B ; Shaun would have been 9km ahead (if he did not stop at point B and maintain the same average speed of 20km/h).

How long does it take Shaun to cover 9km? Answer 9/20 x 60 (minutes) = 27 minutes.

Chin Hong reach at 11.20 + 27 minutes = 11.47am

[Cecilia J]

Thanks.This was from my daughter’s school practice paper.

[MathIzzzFun]

lee tong fong:

Hi, can anyone help me with another question


(6) A total of 84 girls and 231 boys wre involved in a CIP programmeto clean up a section of the beach.
(a) Find the greatest number of groups that can be formed so that all the boys and girls are distributed equally among all the groups.
(b) What is the the total number of children in each group?

Thanks you again

Boys -> 231=21 x 11
Girls -> 84 = 21 x 4
maximum number of groups -> 21
Total number of chilgren in each group-> 11 + 4 = 15

cheers

[lee tong fong]

Thanks for your solutions.


For question 6, I would like to know how do you work out the maximum number of group is 21.

For question 3, is this possible to work out the solution using the (Number of units X Value of units)

[MathIzzzFun]

lee tong fong:

Thanks for your solutions.


For question 6, I would like to know how do you work out the maximum number of group is 21.

For question 3, is this possible to work out the solution using the (Number of units X Value of units)

Find the largest common factor of 84 and 231 which is 21.

cheers.

[S6169]

PapayaDad:

lee tong fong:

Hi, can anyone help me with another question


(3) To make a fruit cake, Mrs Lim used 90% strawberry and 10% mango.
The cost of the mangoes was 1.5 times that of the strawberries.
She spent $6.30 in all for the strawberries and mangoes
How much more would it cost her if she uses 40% strawbeey and 60% mango?

Thanks you again

The cost of the mangoes was 1.5 times that of the strawberries.
interms of cost
1m=1.5s
10m=15s
90s : 15s
6s:1s
7s = 630
s = 90
m = 135

4s=360
6m=810
total=1170

1170 - 630 = 540

Sorry, put S=90, m=135 back to the Q,
9s+m=90*9+135=945 not 630, something wrong?

if you use:
90s : 15s
105s=630
s=6
m=9
then 40s+60m=780
difference 780-630=150

:?

[MathIzzzFun]

lee tong fong:

Hi, can anyone help me with another question


(3) To make a fruit cake, Mrs Lim used 90% strawberry and 10% mango.
The cost of the mangoes was 1.5 times that of the strawberries.
She spent $6.30 in all for the strawberries and mangoes
How much more would it cost her if she uses 40% strawbeey and 60% mango?

Thanks you again

Fruit cake --> 10 units --> 9 units of strawberries + 1 unit of Mangoes

Cost of mangoes was 1.5 times cost of strawberries
--> cost of 1 unit of mangoes was 3/2 times cost of 9 units of strawberries
...note that the statement does not mean that the cost of 1 mango is 1.5 times the cost of 1 strawberry.

Cost of 1 unit of mangoes = 3/5 x $6.30 = $3.78
Cost of 9 units of strawberries = $6.30 - $3.78 = $2.52
Cost of 1 unit of strawberries = $ 2.52 / 9 = $0.28

IF she uses 40% strawberries and 60% mangoes, then cost of the fruit cake will be
--> cost of 4 units of strawberries + cost of 6 units of mangoes
= 4 x $0.28 +6 x $3.78
= $ 23.80

Additional cost --> $23.80 - $6.30 = $17.50



cheers.

[Chalupa]

I need a help to solve this problem. A fruit seller had 600 apples & oranges altogether. After he sold 1/5 of his apples and bought another 60 oranges, the number of oranges was 2/5 the number of apples. How many more apples than oranges were there at first.( Ans.400) .Thanks in advance. :thankyou: :?:

[Chalupa]

Town A and Town B are 375km apart.Wen set off from Town A towards Town B at 1400 at a constant speed of 60km/h.1h later,Nelly set off from Town B towards Town At a constant speed of 80km/h.At what time did the two girls meet on the road? :thankyou:

[MathIzzzFun]

Chalupa:

I need a help to solve this problem. A fruit seller had 600 apples & oranges altogether. After he sold 1/5 of his apples and bought another 60 oranges, the number of oranges was 2/5 the number of apples. How many more apples than oranges were there at first.( Ans.400) .Thanks in advance. :thankyou: :?:

Please do not start a new thread.. post your question at the \"Q&A PSLE thread\"
- http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280
--> go to the last post in the thread
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--------------------------------------------------------
At first, number of apples --> 25 units
In the end,
Number of apples --> 20 units
Number of oranges --> 8 units
At first, number of oranges --> 8 units - 60

Total number of apples and oranges, at first --> 33 units - 60
33 units - 60 --> 600
1 unit --> 20

At first,
number of apples --> 25 x 20 = 500
number of oranges --> 8 x 20 - 60 = 100
500 - 100 = 400
at first, there were 400 more apples than oranges

cheers.