## Q&A - PSLE Math

Academic support for Primary 6 and PSLE
lizawa
BrownBelt
Posts: 665
Joined: Tue Apr 22,
heutistmeintag wrote:oh i see, now I can solve by alegbra.

B=20+G

1/3G+1/4B=19
4G+3B=19*12=228
4G+3*(20+G)=228
4G+60+3G=228
7G=228-60
7G=168
G=24
B=20+24=44
Total number of children invited is (24+44)=68

ok, can someone explain using modelling?
Solve by model :
--------------------
Boys : 12u + 20
Girls : 12u

1/4 boys did not come -> 3u + 5 (you can break 20 into 4 parts, each part is 5)
1/3 girls did not come -> 4u

7u + 5 = 19
1u = 2
Altogether -> 24u + 20 = 48+20 = 68.

kiasuson
BlueBelt
Posts: 239
Joined: Tue Sep 02,
Total Likes:2
Anymore interesting questions that were feedback from the children? My son said the paper was ok as expected..

raysusan
KiasuGrandMaster
Posts: 1414
Joined: Tue Jul 22,
Total Likes:6
lizawa wrote:
heutistmeintag wrote:oh i see, now I can solve by alegbra.

B=20+G

1/3G+1/4B=19
4G+3B=19*12=228
4G+3*(20+G)=228
4G+60+3G=228
7G=228-60
7G=168
G=24
B=20+24=44
Total number of children invited is (24+44)=68

ok, can someone explain using modelling?
Solve by model :
--------------------
Boys : 12u + 20
Girls : 12u

1/4 boys did not come -> 3u + 5 (you can break 20 into 4 parts, each part is 5)
1/3 girls did not come -> 4u

7u + 5 = 19
1u = 2
Altogether -> 24u + 20 = 48+20 = 68.
is this the Q47?

lizawa
BrownBelt
Posts: 665
Joined: Tue Apr 22,
raysusan wrote:
lizawa wrote:
heutistmeintag wrote:oh i see, now I can solve by alegbra.

B=20+G

1/3G+1/4B=19
4G+3B=19*12=228
4G+3*(20+G)=228
4G+60+3G=228
7G=228-60
7G=168
G=24
B=20+24=44
Total number of children invited is (24+44)=68

ok, can someone explain using modelling?
Solve by model :
--------------------
Boys : 12u + 20
Girls : 12u

1/4 boys did not come -> 3u + 5 (you can break 20 into 4 parts, each part is 5)
1/3 girls did not come -> 4u

7u + 5 = 19
1u = 2
Altogether -> 24u + 20 = 48+20 = 68.
is this the Q47?
Hi raysusan,

I don't think so. Q47 should be a 5-mark question. This doesn't look like a 5-mark question to me.

kiasuson
BlueBelt
Posts: 239
Joined: Tue Sep 02,
Total Likes:2
According to my son, Q47 is about speed and the above discussed question is the last question of the paper and it is 5 marks. Anyway, same situation as lizawa... We will not want to probe our son about something that is over and done...They still have another 2 or 3 papers to go...

Priskhipo
YellowBelt
Posts: 21
Joined: Sat Sep 13,
lizawa wrote:
raysusan wrote:
lizawa wrote: Solve by model :
--------------------
Boys : 12u + 20
Girls : 12u

1/4 boys did not come -> 3u + 5 (you can break 20 into 4 parts, each part is 5)
1/3 girls did not come -> 4u

7u + 5 = 19
1u = 2
Altogether -> 24u + 20 = 48+20 = 68.
is this the Q47?
Hi raysusan,

I don't think so. Q47 should be a 5-mark question. This doesn't look like a 5-mark question to me.
Hi All,
This question is the last one and it is 4 marks.

kiasuson
BlueBelt
Posts: 239
Joined: Tue Sep 02,
Total Likes:2
Those interested to know more on PSLE can read this forum.

http://forum.channelnewsasia.com/viewtopic.php?t=183752

cutemum
KiasuNewbie
Posts: 4
Joined: Mon Oct 13,
can anyone help me?

Three girls, Anna, Beatrice and Calista shared a roll of ribbons. Anna's share was 1/4 of the total length of Beatrice's and Calista's ribbon. Beatrice's share was 2/3 of the total length of Anna's and Calista's ribbon. If Anna's share of ribbons is 45 cm less than beatrice's share, what is the total length of the roll of ribbons?.

lizawa
BrownBelt
Posts: 665
Joined: Tue Apr 22,
cutemum wrote:can anyone help me?

Three girls, Anna, Beatrice and Calista shared a roll of ribbons. Anna's share was 1/4 of the total length of Beatrice's and Calista's ribbon. Beatrice's share was 2/3 of the total length of Anna's and Calista's ribbon. If Anna's share of ribbons is 45 cm less than beatrice's share, what is the total length of the roll of ribbons?.
A : B+C
= 1:4

B: A+C
= 2: 3

Note that the total no. of units in both cases are equal, ie 5 units. So the size of unit in each case is the same.

A: B
= 1:2
Since A has 45cm less than B,
1 unit = 45 cm
5 units = 45 *5 = 225 cm

Total length = 225cm.

cutemum
KiasuNewbie
Posts: 4
Joined: Mon Oct 13,
yeah, that's the answer, thank you so much lizawa....