Q&A - PSLE Math

[tianzhu]

mlim321:

tianzhu:

BBB + RRR ------ 129

Hi tianzhu,

how do you get \"BBB + RRR = 129\"?

Thanks a lot!

Hi

B + R ------ 43

(x3)
(3B + 3R ----- 129)

BBB + RRR ------ 129

Best wishes

[Easy-going]

My niece asked me these two questions which I cannot solve. Pls help.

Qn1

[Easy-going]

Hi can someone help me with this question.

Question One
There were 225 apples and 253 oranges in Box A. There were 260 apples and 212 oranges in Box B. Mr Chia moved some apples and oranges from Box B to Box A.
In the end, 40% if the fruits in Box A and 70% of the fruits in Box B were apples. How many fruits did Mr Chia move from Box B to Box A?

[SAHM88]

Please help!

1. There were 1000 students at the parade ground and indoor sports hall. 40% of the 600 students at the parade ground were girls. 60% of the students at the indoor sport hall were girls. After some students in both venues moved from one venue to the other, 30% of the students in the parade ground and 70% of the students at the indoor sports hall were girls. How many students were there in the indoor sports hall after the movement had taken place?

2. A large warehouse had a total of 2180 black, red and white T-shirts for sales. The ratio of the number of black T-shirts to the number of red T-shirts was 3:1. After 2/5 of the black T-shirts, 1/3 of the white T-shirts and none of the red T-shirts were sold on the first day, there were 1504 T-shirts left. How many red T-shirts did the warehouse have at first?

Thanks

[MathIzzzFun]

Easy-going:

Hi can someone help me with this question.

Question One
There were 225 apples and 253 oranges in Box A. There were 260 apples and 212 oranges in Box B. Mr Chia moved some apples and oranges from Box B to Box A.
In the end, 40% if the fruits in Box A and 70% of the fruits in Box B were apples. How many fruits did Mr Chia move from Box B to Box A?

Hi

this was discussed earlier - http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&start=6480

http://i46.tinypic.com/2h2easg.png\">

cheers.

[MathIzzzFun]

SAHM88:

Please help!

1. There were 1000 students at the parade ground and indoor sports hall. 40% of the 600 students at the parade ground were girls. 60% of the students at the indoor sport hall were girls. After some students in both venues moved from one venue to the other, 30% of the students in the parade ground and 70% of the students at the indoor sports hall were girls. How many students were there in the indoor sports hall after the movement had taken place?

2. A large warehouse had a total of 2180 black, red and white T-shirts for sales. The ratio of the number of black T-shirts to the number of red T-shirts was 3:1. After 2/5 of the black T-shirts, 1/3 of the white T-shirts and none of the red T-shirts were sold on the first day, there were 1504 T-shirts left. How many red T-shirts did the warehouse have at first?

Thanks

Q1.
this was discussed before - http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=777637&hilit=1000+students#p777637

it is similar to the Apples and oranges question, one post before this.



Q2.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=781608&hilit=2180+black#p781608


cheers.

[mlim321]

Thanks tianzhu for the clarification!

[Easy-going]

Beaker A and Beaker B contain some water. If 46.5ml of water is drained from Beaker A, the volume of the water in beaker A will be 60% that of the water in Beaker B.

If 35.2 ml of water is drained out from Beaker B, the volume of the water in Beaker B will be 85% that of the water in Beaker A.
What is the tota volume of water in Beaker and Beaker B?

[its888me]

The figure below shows 3 different rectangles, X, Y and Z. 3/10 of X and 40% of Z is shaded. The shaded area of X is the same as the shaded area of Z. What fraction of the figure is unshaded if 60% of Y is shaded?


My child got the answer 4/7, but the answer is 31/43. What is wrong? Can someone help? Thanks! http://i49.tinypic.com/15dlah.jpg\">

[MathIzzzFun]

its888me:

The figure below shows 3 different rectangles, X, Y and Z. 3/10 of X and 40% of Z is shaded. The shaded area of X is the same as the shaded area of Z. What fraction of the figure is unshaded if 60% of Y is shaded?


My child got the answer 4/7, but the answer is 31/43. What is wrong? Can someone help? Thanks! http://i49.tinypic.com/15dlah.jpg\">

Hi

X, shaded:unshaded = 3 : 7 --> 6 units: 14 units
Z, shaded:unshaded = 2 : 3 --> 6 units: 9 units
Y, shaded:unshaded = 3 : 2 --> 12 units : 8 units --- Y, total --> 20 units
total unshaded --> (14 + 9 + units = 31 units
total area --> 14 units (X, unshaded) + 9 units (Z, unshaded) + 20 units (Y) = 43 units
fraction of figure that is unshaded = 31/43

cheers.