Q&A - PSLE Math

[tianzhu]

Hi moderators


Please delete.

Best wishes

[superksmum]

tianzhu:

superksmum:

Hi help needed!


A tank was half filled with water. More water was added until it was 2/3 full. The ratio of the mass of the tank when it was 1/2 full to the mass of the tank when it was 2/3 full was 7:9.

a) What is the ratio of the volume of water in the tank when it was 1/2 full to the volume of the water went he tank was 2/3 full?

b) the mass of the empty tank was 500g. What was the total mass of the tank and water when the tank was 2/3 full?

Hi

Where is this question from?

Perhaps some info needed for (b) might be missing.

The answer to (a) is 3:4

Divide the tank into 6 units

1/2 filled ----- 3 units
2/3 filled ----- 4 units.

Best wishes

Hi Tianzhu,

Thank you.
It is a worksheet by the school teacher for the kids to practice.

[superksmum]

Hi Tianzhu,


I have checked the paper. This is what is stated in the paper.

[Michaelia0816]

tianzhu:

Michaelia0816:

7)Car x, car y and car z together crossed point a at noon as they were heading for point b. by 1.30 pm, car x was 75 km from point a and car y was ahead of car x by 6km. By this time, car x had already travelled the combined distance of the other two cars from point a. What was the difference in speed between car z and y?

Hi

Please check.

Best wishes

Sorry, it should be car z!

[Michaelia0816]

Oh the car question I already solved it!

[Michaelia0816]

Tianzhu help!

20) Peter set off from X for Z at 10.45 am at a uniform speed of 64km/h. 20 minutes later, Dave set off from Z for X at a uniform speed and he passed Peter at Y.
a) Find the speed at which Dave was travelling.
b) At what time would Dave arrived at X?
X. 96km Y. 140km Z
||_______|

[Michaelia0816]

Sorry for the model I try to post on the pervious one.

It should be distance between XY is 96km and the distance between YZ is 140km!!!

[Michaelia0816]

Help here also!

Ricky started driving at the same time as Mike from the city to a town 180 km away. The ratio of Ricky’s average speed to Mike’a average speed was 3:5. In all, Ricky took 1 h more to cover the whole distance than Mike.
a) How long did Ricky took to cover the distance?
b) What the speed at which Mike was driving?

[Michaelia0816]

Also this one, help!


The ratio of the average speed of Ali, Ben and Carl was 2:3:4 respectively. They started driving at the same time and after 5h, they had covered a total of 675 km. What was the average speed of Ben?

[Michaelia0816]

Sue and Ken both set off at the same time from Joycity for Kimtown, 320 km away. For the first 3/8 of the journey, Ken 's average speed was 75% that of Sue. Sue’s average speed for the whole journey was 80km/h. If ken wanted to catch up with sue at Kimtown , at what speed must he drive for the rest of the distance?