Q&A - PSLE Math

[pixiedust]

Appreciate help with this :


In a game, the number of points Mr. Tan had to the number of points Mr. Lim had was 7:4. After Mr. Tan lost 85 points and Mr. Lim gained 85 points, the ration of points Mr. Tan had to that of Mr. Lim became 1:3.

a) how many points did Mr. Tan have at first ?
b) how many more points did Mr. Lim have than Mr. Tan at the end ?

[bobsg01]

Hi,


Don't quite understand how the answer was done.

<a href=\"http://tinypic.com?ref=2ic5sm9\" target=\"_blank\"><img src=\"http://i52.tinypic.com/2ic5sm9.jpg\" border=\"0\" alt=\"Image and video hosting by TinyPic\"></a>

Answer given is (1)

Shouldn't the answer be 4

No. of Bookmarks 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
No. of Pupils 2 ? 6 8 10 .....

<a href=\"http://tinypic.com?ref=2nthag9\" target=\"_blank\"><img src=\"http://i54.tinypic.com/2nthag9.jpg\" border=\"0\" alt=\"Image and video hosting by TinyPic\"></a>

Q5

Answer given is (2)

Shouldn't the answer be SW

N
X
W E


135 degrees

S

:?:

Thanks for the help.

[bobsg01]

http://i52.tinypic.com/2ic5sm9.jpg\">

[bobsg01]

http://i54.tinypic.com/2nthag9.jpg\">

[bobsg01]

http://i55.tinypic.com/2q16qsy.jpg\">


Sorry for the messy post as I was having problem with the image upload.

:lovesite:

[tianzhu]

pixiedust:

Appreciate help with this :


In a game, the number of points Mr. Tan had to the number of points Mr. Lim had was 7:4. After Mr. Tan lost 85 points and Mr. Lim gained 85 points, the ration of points Mr. Tan had to that of Mr. Lim became 1:3.

a) how many points did Mr. Tan have at first ?
b) how many more points did Mr. Lim have than Mr. Tan at the end ?

Hi

A quick one .

Mr. Tan lost 85 points and Mr. Lim gained 85 points, so the total points remain the same.

Start ------- Mr Tan: Mr Lim ------- 7:4 --------- (11)
End ------- Mr Tan: Mr Lim ------- 1:3 -------- (4)

Make the total number of units the same.

Start ------- Mr Tan: Mr Lim ------- 7:4 ---------28:16 -------- (44)
End ------- Mr Tan: Mr Lim ------- 1:3 -------- 11:33 ------- (44)

17 units ------ 85
1 unit ------ 5

Mr Tan -------- 28 x 5 ------ 140\t

33 x 5 ------- 165
11 x 5 ------- 55
Mr Lim ------- (165 – 55) ------- 110

Best wishes

[tianzhu]

bobsg01:

http://i55.tinypic.com/2q16qsy.jpg\">

Hi

6 x 2 ------- 12 (6 pupils making 2 bookmarks each)
20 - 12 ------- 8

North is correct, rotate 135 degrees clockwise

Best wishes

[pixiedust]

Thank you tianzhu. I pay you to tutor my son, can ? :lol:

[ozora]

tianzhu:

Hi


In this question, a student should note that the number of apples and oranges remains the same in both scenarios.

A student who is familiar with SE could proceed to use it. If not, he/she could solve it using the alphabet method or pictorially.

In this illustration, I’ve done it pictorially. As usual, I’ve put in more details than necessary because I wanted to show the flow of events. Once you understand the concept, you may express the solution in your own way.

Best wishes.

http://farm6.static.flickr.com/5268/5691587923_36c3de836e_z.jpg\">

thanks for the help/.. it really makes me understand better to assist my nephews .thanks again

[ozora]

sorry need guide about these questions.

a)The number of 20cents coins to $1 coins in Jane’s box is 5:4. She took out 8 $1 coins and exchanged them into 20 cents coins of the same value. The ratio of the number of 20cents coins to $1 coins became 15: 4. What was the amount of money Jane has?
I used equivalent ratio and got $35. I wondered is the answer correct.

Is it possible to use model or units method? If yes, how?

b) Shop A has 164 more customers than shop B . After 1/4 of the customers in shop A and went to shop B, there was 48 more customers in shop A than in shop A. How many customers were there in shop A and shop B respectively?