Q&A - PSLE Math

[tianzhu]

kyp71:

Ya u r right. Typo error.

Mr smith had 1.5 litre of white pain in Tin A and 1.25 litre of red paint in Tin B. He poured 750ml of red paint from Tin B into Tin A. Then he poured some of the mixture in Tin A back into Tin B. if 7/11 of the final mixture in Tin B was made up of red paint, what was the volume of the mixture in Tin A that Mr smith had poured into Tin B ?

Hi

Just curious, where did you get this question from?

You may use MD or work using units.

At first

Tin A
White paint ----- 1500 ml

Tin B
Red paint ----- 1250 ml

He poured 750ml of red paint from Tin B into Tin A.

Tin A
White paint ----- 1500 ml
Red paint ----- 750 ml
White:Red ------ 2:1

Tin B
Red paint ----- 500 ml

2 units of white paint and 1 unit of red paint were transferred from Tin A to Tin B

Tin B
Red paint ----- 500 + 1 unit ------- 7 parts (7/11)

White paint ------ 2 units ------ 4 parts (4/11), this gives 1 unit ------ 2 parts

500 + 2 parts ------- 7 parts
500 ------ 5 parts
Hence, 1 part ------ 100

Therefore the volume of mixture from A to B is 3 units (6 parts) which is 600ml.

Best wishes

[kyp71]

Set in one of the paper given by her teacher.

[kyp71]

tianzhu:

kyp71:

Ya u r right. Typo error.

Mr smith had 1.5 litre of white pain in Tin A and 1.25 litre of red paint in Tin B. He poured 750ml of red paint from Tin B into Tin A. Then he poured some of the mixture in Tin A back into Tin B. if 7/11 of the final mixture in Tin B was made up of red paint, what was the volume of the mixture in Tin A that Mr smith had poured into Tin B ?

Hi

Just curious, where did you get this question from?

You may use MD or work using units.

At first

Tin A
White paint ----- 1500 ml

Tin B
Red paint ----- 1250 ml

He poured 750ml of red paint from Tin B into Tin A.

Tin A
White paint ----- 1500 ml
Red paint ----- 750 ml
White:Red ------ 2:1

Tin B
Red paint ----- 500 ml

2 units of white paint and 1 unit of red paint were transferred from Tin A to Tin B

Tin B
Red paint ----- 500 + 1 unit ------- 7 parts (7/11)

White paint ------ 2 units ------ 4 parts (4/11), this gives 1 unit ------ 2 parts

500 + 2 parts ------- 7 parts
500 ------ 5 parts
Hence, 1 part ------ 100

Therefore the volume of mixture from A to B is 3 units (6 parts) which is 600ml.

Best wishes

They only state mixture were transferred from A to B and how u derive at 2 units of white paint and 1 unit of red paint were transferred from Tin A to Tin B ? Please explain ? Thks

[tianzhu]

kyp71:

They only state mixture were transferred from A to B and how u derive at 2 units of white paint and 1 unit of red paint were transferred from Tin A to Tin B ? Please explain ? Thks

Hi

To begin with, this is not an easy question for P6 students.

The ratio of white paint to red paint in Tin A 1s 2:1 (1500:750).

Hence, we have a volume of mixture containing 2 units (W) and 1 unit (R) being transferred.

Best wishes

[Chan09]

Mgs 2011:

Distance between A and B is116km. The bus left A and headed for B. some time later a car left A and headed B along same route. Along the way the car overtake the bus and arrive at B, 45 minutes earlier than the bus. When the car arrived at B,the bus had travelled 5/8 of the distance. What was the speed of the bus?

I had 36.25 km/h though not sure if this is right?

[tianzhu]

Chan09:

Mgs 2011:

Distance between A and B is116km. The bus left A and headed for B. some time later a car left A and headed B along same route. Along the way the car overtake the bus and arrive at B, 45 minutes earlier than the bus. When the car arrived at B,the bus had travelled 5/8 of the distance. What was the speed of the bus?

I had 36.25 km/h though not sure if this is right?

Hi

For Speed question, it’s useful to start with a simple diagram.

116/8 ------ 14.5

14.5*3 ------- 43.5

Speed of bus ------- 43.5*(4/3) -------58 km/h

Best wishes

[2DMommy]

Please help me with this question :


Keane bought some marbles and gave half of them to Leon. Leon bought some stamps and gave half of them to Keane.

Keane used stamps and Leon gave away marbles. The ratio of the number of stamps to the number of marbles Keane had left then became 1 : 7 and ratio of the number of stamps to the number of marbles Leon had left became 1 : 5.
How mnay stamps did Leon buy ?

Thanks !

[MathIzzzFun]

2DMommy:

Please help me with this question :


Keane bought some marbles and gave half of them to Leon. Leon bought some stamps and gave half of them to Keane.

Keane used stamps and Leon gave away marbles. The ratio of the number of stamps to the number of marbles Keane had left then became 1 : 7 and ratio of the number of stamps to the number of marbles Leon had left became 1 : 5.
How mnay stamps did Leon buy ?

Thanks !

Hi

http://tinyurl.com/mathizzzfun-Cx-UP-1205-01

cheers.

[2cor41618]

2DMommy:

Please help me with this question :


Keane bought some marbles and gave half of them to Leon. Leon bought some stamps and gave half of them to Keane.

Keane used stamps and Leon gave away marbles. The ratio of the number of stamps to the number of marbles Keane had left then became 1 : 7 and ratio of the number of stamps to the number of marbles Leon had left became 1 : 5.
How mnay stamps did Leon buy ?

Thanks !

Hi, did u miss out some info on the highlighted part?

[sleepyqueen]

2cor41618:

2DMommy:

Please help me with this question :


Keane bought some marbles and gave half of them to Leon. Leon bought some stamps and gave half of them to Keane.

Keane used 5 stamps and Leon gave away 11 marbles. The ratio of the number of stamps to the number of marbles Keane had left then became 1 : 7 and ratio of the number of stamps to the number of marbles Leon had left became 1 : 5.
How mnay stamps did Leon buy ?

Thanks !

Hi, did u miss out some info on the highlighted part?

Updated the question