Q&A - PSLE Math

[atutor2001]

Full.Cream:

think you missed the 1st 3 days of the pear feast!

Thanks the answer is 1, was dreaming.

[youngmum]

Thanks everyone!

[N3SKiasu]

Hi all,

Need your help on this Rosyth Prelim 2008 Q48 (I have searched thru past pages and could not find any discussion on this question, hope my eyes are working fine by browsing thru the 50+ pages and it is not repeated):

Ning and Zongwei jogged to and fro repeatedly along a straight path in a park between 2 points A and B.
Ning jogged at a uniform speed of 4m/s.
Zongwei jogged at uniform speed of 6m/s.
They started jogging from opposite directions at the same time as shown below.
Ning ------> <----------Zongwei
A---------------------X---------------------Y-------------------B

They first met one another at point X. The second time they met was at point Y.
a) Given that the distance between X and Y is 160m. Find the distance between A and B. (Answer given : 400m)
b) If they started jogging at 8am, how long did they take to meet again for the third time? (Express your answer in minutes and seconds). (Answer given : 3m20s)

Do you consider this is as a challenging question?
A bit worried for DD now as she could not solve this sort of question at this point...and so do I, helpless mom...counting down...
TIA.

[N3SKiasu]

Would like to check on the answer for SCGS Prelim 2008 Q23:


A 200m long MRT train took 20 min to pass through a tunnel completely.
If the MRT train travelled at an average speed of 120 m/min, find the length of the tunnel.

Solution:
120m/min x 20 min = 2400 m
2400m - 200 m = 2200m

But the answer given is 2300 m. Just wondering if the answer given is correct?

[tianzhu]

N3SKiasu:

Hi all,

Need your help on this Rosyth Prelim 2008 Q48 (I have searched thru past pages and could not find any discussion on this question, hope my eyes are working fine by browsing thru the 50+ pages and it is not repeated):

Hi
Dharma had answered this Q.Please go to pg 54.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=280&postdays=0&postorder=asc&start=795

[tianzhu]

N3SKiasu:

120m/min x 20 min = 2400 m
2400m - 200 m = 2200m
But the answer given is 2300 m. Just wondering if the answer given is correct?

Hi
You are right.
The answer is 2200m.

[N3SKiasu]

tianzhu:

N3SKiasu:

Hi all,

Need your help on this Rosyth Prelim 2008 Q48 (I have searched thru past pages and could not find any discussion on this question, hope my eyes are working fine by browsing thru the 50+ pages and it is not repeated):

Hi
Dharma had answered this Q.Please go to pg 54.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=280&postdays=0&postorder=asc&start=795

Thank you so much Tianzhu, oh it was just 3 pages before this, I must have browsed thru too quickly. Millions thanks!

[N3SKiasu]

tianzhu:

N3SKiasu:

120m/min x 20 min = 2400 m
2400m - 200 m = 2200m
But the answer given is 2300 m. Just wondering if the answer given is correct?

Hi
You are right.
The answer is 2200m.

Thanks again Tianzhu for the confirmation.

[k1ndan]

Four Friends, Alice, Billy, Carol and David shared a total of 81 chocolates. Alice received 4/5 of the total number of chocolates received by Billy. Carol and David. Billy received 2/3 of the total number of chocolates received by Carol and David. Carol received twice as many chocolates as David.


(a) What fraction of all the chocolates does Billy have?

(b) How many chocolates did Alice receive?

[Sahimi]

a) A : B+C+D

4 : 5

B : C+D
2 : 3


A : B : C : D
4 : 2 : 2 : 1

81 divide by 9 times 2 = 18
18/81 = 2/9

b) 1u = 81 divide by 9 = 9
9 times 4 = 36