Q&A - PSLE Math

[MathIzzzFun]

superksmum:

Sorry another 2 questions:


1) A glass bottle filled with 6 identical ball bearings weighs 1.05kg. The same bottle when filled with 8 marbles weighs 830g. The mass of each ball-bearing is five times the mass of each marble. What is the mass of the empty glass?


Thank you.

6 ball bearings --> 30 marbles
30 - 8 = 22
mass of 22 marbles --> 1050-830= 220
1 marble --> 10g
Mass of empty bottle --> 830 - 10 x 8 = 750g

cheers.

[MathIzzzFun]

superksmum:

Sorry another 2 questions:



2) John donated 1/4 of his cards and Joseph donated 2/3 of his cards. They have the same number of cards left. What is the ratio of the number of cards John has to the number of cards Joseph has at first?

Thank you.

Each had same number of cards left:

3/4 John's cards = 1/3 Joseph's cards
3/4 John's cards = 3/9 Joseph's cards
John's cards : Joseph's cards --> 4 : 9

cheers.

[superksmum]

MathIzzzFun:

superksmum:

Sorry another 2 questions:


1) A glass bottle filled with 6 identical ball bearings weighs 1.05kg. The same bottle when filled with 8 marbles weighs 830g. The mass of each ball-bearing is five times the mass of each marble. What is the mass of the empty glass?


Thank you.

6 ball bearings --> 30 marbles
30 - 8 = 22
mass of 22 marbles --> 1050-830= 220
1 marble --> 10g
Mass of empty bottle --> 830 - 10 x 8 = 750g

cheers.

:thankyou: MathIzzFun

[MathIzzzFun]

superksmum:

Please help,


A large warehouse had a total of 2180 black, red and white t-shirts for sale. 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, the were 1504 t-shirts left. How many red t-shirts did the warehouse have at first?

Thank you.

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

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=801372&hilit=A+large+warehouse#p801372

cheers.

[superksmum]

MathIzzzFun:

superksmum:

Sorry another 2 questions:



2) John donated 1/4 of his cards and Joseph donated 2/3 of his cards. They have the same number of cards left. What is the ratio of the number of cards John has to the number of cards Joseph has at first?

Thank you.

Each had same number of cards left:

3/4 John's cards = 1/3 Joseph's cards
3/4 John's cards = 3/9 Joseph's cards
John's cards : Joseph's cards --> 4 : 9

cheers.

:thankyou: MathIzzFun

[superksmum]

MathIzzzFun:

superksmum:

Please help,


A large warehouse had a total of 2180 black, red and white t-shirts for sale. 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, the were 1504 t-shirts left. How many red t-shirts did the warehouse have at first?

Thank you.

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

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&p=801372&hilit=A+large+warehouse#p801372

cheers.

:thankyou: I remember seeing it but just can't seem to find it. :slapshead:
Have a good day.

Cheers

[oosh]

Hi,


Needed some help on this question.

Jimmy runs 4km/h faster than he walks. He walks 1 1/2hr and runs the rest of the time over a distance of 6Km. If Jimmy walks as fas as he runs, find the amount of time he spends running.

Answer given = 1/2hr but my answer is 3/4hr. Will greatly appreciate any assistance.

[oosh]

Please help


Sean earns a% more than Alice. Cathy earns 30% less than Alice. If Alice earns $1500, what is the total amount of money earned by Alice, Cathy and Sean?
(Answer: $(4050 + 15a)

TIA

[MathIzzzFun]

superksmum:

Pls help:


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 sports 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?

Thank you.

http://i47.tinypic.com/35jxa15.png\">

cheers.

[MathIzzzFun]

oosh:

Please help


Sean earns a% more than Alice. Cathy earns 30% less than Alice. If Alice earns $1500, what is the total amount of money earned by Alice, Cathy and Sean?
(Answer: $(4050 + 15a)

TIA

Alice --> $1500
Cathy --> 0.7 x $1500 = $1050
Sean --> (1+a/100) x $1500 = $1500 + 15a
Total --> $(4050+15a)

cheers.