Q&A - PSLE Math

[enoawng]

James Ang:

enoawng:

Can any help?


There were 186 adults in an auditorium. When 7/12 of the men and 4/9 of the women left the auditorium, the total number of adults who remained became 90. How many men were there in the auditorium at first?

let me try;

12/12 - 7/12 = 5/12 of men left behind
9/9 - 4/9 = 5/9 of women left behind

5/12 of men and 5/9 of women = 90
1/12 of men and 1/9 of women = 18
9/12 of men and 9/9 of men = 18x9 = 162
3/12 of men = 186 -162 = 24
12/12 of men = 24 x 4 = 96 men.

There are 96 men in the auditorium at first.

Thanks. However I think one step is missing for clarity, right?
9/12 of men and 9/9 of WOmen = 18x9 = 162 .........(1)
12/12 of men + 9/9 of WOmen = 186 .....................(2)
Subtracting (2) from (1)
3/12 of men = 186-162=24

Cheer

[Dharma]

http://www.postimage.org/

[small]

Drdj:

Drdj:

Hi there,


I have a question from Red Swastika Prelim 2008 Paper.
The answer seems to give the area of the grille (784 cm2), but length of iron needed to make the grille should be the circumference, and length. Am I correct?

HI Drdj,

agrred with Tianzhu, I think the answer should be 344 cm

28 x 4 = 112 ( the four sides)
28 x 2 = 56 ( the inner two bars)
2 x 22 / 7 x 7 x 4 = 176 ( the 4 circles )

112+ 56 + 176 = 344 cm

[fxchow]

Hi,


Can someone help to solve this question. TIA.

James had some fishes in a tank. 15 were goldfish and the rest were guppies and angelfish.
The ratio of the number of goldfish to the number of guppies was 3:2 and the ratio of the number of guppies to the number of angelfish was 1:5. If James added 24 fish into the tank, the number of guppies would increase by 50%, and the angelfish would increase by 40%.
How many goldfish were added?

P/S: My girl told me that the question got mistake, please see if you can solve it. Question from school with no answer provided.

[Dharma]

fxchow:

Hi,


P/S: My girl told me that the question got mistake, please see if you can solve it. Question from school with no answer provided.

You girl is right.
http://www.postimage.org/

[Tang]

Dharma:

tianzhu:

Hi, hope this helps.

http://farm4.static.flickr.com/3447/3790867316_9c928f2e6d_o.jpg\">

This is small add on to Tianzhu's brilliant illustration.


http://www.postimage.org/

3 u = 2 p

1 p = 1 u + 1
2 p = 2 u + 2

3 u = 2 u + 2

1 u = 2; 1 p = 3

[fxchow]

Dharma:

fxchow:

Hi,


P/S: My girl told me that the question got mistake, please see if you can solve it. Question from school with no answer provided.

You girl is right.
http://www.postimage.org/

Hi Dharma,

Thanks for your reply. Have a nice weekend.

[enoawng]

can anyone help?


John was n years old when his mother was 36 years old. Today, his mother is 3 times as old as John.
a) Express John’s age now in terms of n
b) What is John’s age now if n=8?

[Dharma]

enoawng:

can anyone help?


John was n years old when his mother was 36 years old. Today, his mother is 3 times as old as John.
a) Express John’s age now in terms of n
b) What is John’s age now if n=8?

http://www.postimage.org/

[David Koriadi]

Sandy bought some apples and oranges. The number of apples was 1 ¼ times the number of oranges. After she packed the apples into boxes of 10 and oranges into boxes of 6, she found that she had 2 more boxes of oranges than apples. How many apples did she buy at first?