Q&A - PSLE Math

[kiasuson]

My son’s answer is 68 and I think he is correct.

[heutistmeintag]

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?

[heutistmeintag]

kiasuson:

My son's answer is 68 and I think he is correct.

Thanks for providing the missing link. Happy for your son but sad for mine, he didnt get it.

[lizawa]

heutistmeintag:

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]

Anymore interesting questions that were feedback from the children? My son said the paper was ok as expected…

[raysusan]

lizawa:

heutistmeintag:

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]

raysusan:

lizawa:

[quote=\"heutistmeintag\"]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?[/quote]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]

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]

lizawa:

raysusan:

[quote=\"lizawa\"]
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.[/quote]Hi All,
This question is the last one and it is 4 marks.

[kiasuson]

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