Q&A - PSLE Math

[Daddy]

Hi all,

Posting picture problem on smart phone.
when I post picture using 640x480 and above the picture shown 1/2 of it.
When I use 320x240 it's ok.
Is it my phone problem?
Anybody encounter this problem.

[Ender]

Volume of water in Tank A = 1200t
Tank A base area = 20 X 15 =300 cm2
Therefore height of water in Tank A, Ha = 1200t/300 = 4t


Volume of water in Tank B at first = 20X18X15 = 5400cm3
Drained volume = 720t
Volume 0f water in Tank B left = 5400-720t
Base area of Tank B = 20X18 = 360cm2
Therefore heigh of water in Tank B, Hb = (5400-720t)/360 = 15-2t

a) Condition when both heights are equal, Ha = Hb,
4t=15-2t
15=6t
t=2.5min

b) Height at the point of time = 4(2.5) = 10cm

[Daddy]

Thank Ender.

Volume of water in Tank A = 1200t
What is the t and not l or cm3?

[Ender]

t=time in minutes.. ...Flowrate (1200cm3/min) X Time(min) = Volume (cm3)

[Daddy]

Thank Ender.

[pirate]

Just convert flow rate (litres per minute) to level change rate (cm per minute).

Level change rate for tank A is 1200/20/15 = 4 cm per minute
Level change rate for tank B is 720/18/20 = 2 cm per minute

(a) After t minutes, level of water in A = 4t; level of water in B = 15-2t

Rest just copy Ender's working. I am lazy.

[COOKIE64]

Amos bought some chickens and gave half of them to Nathan. Nathsn bought some ducks and gave half of them to Amos .
Amos sold 6 ducks and Nathsn sold 9 chickens. In the end the number of ducks Amos had was 1/7 oF the number of his remaining chickens and the number of ducks Nathan had was 1/4 of the number of his remaining chickens .

How many chickens did Amos buy?

How many chickens and ducks did they have altogether in the end ?

[COOKIE64]

At 10.00 am Joash was cycling from Mivo city towards Purmei town. At the same time , Miriam was cycling from Purmei town towards Mivo city on the same route as Joash. Cycling at a speed of 4 km/h faster than MIriam, they would pass each other 400 meters away from the midpoint .
What time did they pass each other?

If Joash took another 4 minutes to reach Purmei town, what time would Miriam reach Mivo city?

[Swift Formula]

Hi all,

Posting picture problem on smart phone.
when I post picture using 640x480 and above the picture shown 1/2 of it.
When I use 320x240 it's ok.
Is it my phone problem?
Anybody encounter this problem.

It is normal. U just need to click the image for it to blow up.
Preferably Open In New Tab.
Copy Image Location. Ctrl-V to paste in new tab.
This forum auto-crop away part of the picture to display in forums.
Best resolution = Biggest resolution = 1024 pixels in length

[Swift Formula]

Amos bought some chickens and gave half of them to Nathan. Nathsn bought some ducks and gave half of them to Amos .
Amos sold 6 ducks and Nathsn sold 9 chickens. In the end the number of ducks Amos had was 1/7 oF the number of his remaining chickens and the number of ducks Nathan had was 1/4 of the number of his remaining chickens .

How many chickens did Amos buy?

How many chickens and ducks did they have altogether in the end ?

At first Amos and Nathan has the same number of C and D .
Amos = D-6 and C
Nathan = D and C-9
7x(D-6) = C
4D = C-9

Using the above 2 equation, do you still need further help?