Q&A - PSLE Math

[MathIzzzFun]

Cheerfuldad:

Hi,


PL help.

Q. Sally baked some cookies to sell. 3/4 of them were chocolate cookies and the remaining were almond cookies. After she sold 5/6 of chocolate cookies and 210 almond cookies, she had 1/5 of the cookies left. How many cookies did she sell?

TIA.

Regards

Hi

this was discussed before - http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=27&t=280&start=3760

cheers.

[Belle2011]

tianzhu:

Belle2011:

Dear all,

I need some help, please.

Ahmad and Halim together took 5 days to paint their house. If Ahmad and Halim work together for 2 days, followed by Ahmad working alone for 8 days, Halim will take 1 more day to complete the remaining work. How long will Ahmad take to paint the house all by himself?

Thank-you.

Hi Belle2011

This question touches on “Rates”.

There is more than one way to solve it.
One possible solution is:

When Ahamd and Halim work together, they can paint their house in 5 days.
In 1 day, they can paint 1/5 of their house or 1 unit.

Hence, 1 day of Ahmad + 1 day of Halim ----- 1 unit

In 2 days, they can paint 2/5(2 units) of their house, this means 3/5(3 units) of their house is left unpainted.

8 days of Ahmad + 1 day of Halim ----- 3 units
1 day of Ahmad + 1 day of Halim ----- 1 unit

Therefore, 7 days of Ahmad ----- 2 units
17.5 days ----- 5 units(whole house)

Ahmad took 17.5 days to paint the house all by himself.

Best wishes

Thank-you, tianzhu.

[Belle2011]

In every minute, 3 times as much water flows out of tap A as tap B into 2 empty containers, X and Y. After 20 minutes, container X is 2/5 filled with water and the height of water level in container X is the same as that of container Y. Given that the base area of container X is 30cm x 25cm and that of container Y is 50cm x 45cm, how many litres of water can container X hold?

(ans is 56.25 litres)

Thank-you.

[MathIzzzFun]

Cheerfuldad:

Hi,


Q. mei ing and Raja started on a 36km cycling trip at the same time. They cycled at the same speed fit the 12 mm. For the remaining 24km, Meiling cycled at a faster speed. She arrived at the finishing point 10 minutes before Raja who was 4km behind her. Raja did not change his speed throughout the trip and he completed the trip at 11 10.

A) At what time did the trip start?

B). What was Meiling's average speed for the remaining 24km of the trip in m/min?

TIA.

Hi

I supposed the 2nd sentence should be :\"They cycled at the same speed for the first 12 km\" ?

If it is, then:

Raju is 4km behind when Meiling reached the finishing point.
Time to cycle 4km = 10min, Raju's speed = 4km x 6 km/h = 24km/h
Time taken to cycle entire distance = 36/24 h = 1.5h
Start time = 1110 - 1.5h = 0940

For the last 24km, when Meiling reached finishing point, Raju was 4km behind ie Raju cycled only 20km,
Meiling's speed = 24/20 x 24km/h = 1.2 x 24 x 1000/60 m/min = 480m/min

cheers.

[tianzhu]

Belle2011:

In every minute, 3 times as much water flows out of tap A as tap B into 2 empty containers, X and Y. After 20 minutes, container X is 2/5 filled with water and the height of water level in container X is the same as that of container Y. Given that the base area of container X is 30cm x 25cm and that of container Y is 50cm x 45cm, how many litres of water can container X hold?

(ans is 56.25 litres)

Hi Belle2011

Good Morning.

Perhaps, there may be some missing information.

To get the given answer of 56.25 litres, one needs to have a height of 75cm.

Best wishes

[tianzhu]

Belle2011:

Thank-you, tianzhu.

Hi Belle2011

You're welcome.

Best wishes

[Cheerfuldad]

HI MathIzzzFun,


Thank you for your answer!

Regards

MathIzzzFun:

Cheerfuldad:

Hi,

Q. mei ing and Raja started on a 36km cycling trip at the same time. They cycled at the same speed fit the 12 mm. For the remaining 24km, Meiling cycled at a faster speed. She arrived at the finishing point 10 minutes before Raja who was 4km behind her. Raja did not change his speed throughout the trip and he completed the trip at 11 10.

A) At what time did the trip start?

B). What was Meiling's average speed for the remaining 24km of the trip in m/min?

TIA.

Hi

I supposed the 2nd sentence should be :\"They cycled at the same speed for the first 12 km\" ?

If it is, then:

Raju is 4km behind when Meiling reached the finishing point.
Time to cycle 4km = 10min, Raju's speed = 4km x 6 km/h = 24km/h
Time taken to cycle entire distance = 36/24 h = 1.5h
Start time = 1110 - 1.5h = 0940

For the last 24km, when Meiling reached finishing point, Raju was 4km behind ie Raju cycled only 20km,
Meiling's speed = 24/20 x 24km/h = 1.2 x 24 x 1000/60 m/min = 480m/min

cheers.

[Hifive]

Hi all


Need help with the following questions:

1. http://www.flickr.com/photos/62186744@N04/6028704702/

2. Tom bought a vase which he decides to sell. If he sells the vase at a discount of 20%, he makes a gain of $150. If he sells it at 45% discount, he loses $325. How much did Tom pay for his vase?

Thanks in advance!

[bobsg01]

Need your kind help for this question.


Thanks in advance.

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[stary]

bobsg01:

Need your kind help for this question.


Thanks in advance.

http://i54.tinypic.com/2qtctci.jpg\">

The question was discussed earlier on. Cheerio!