2021 PSLE Discussions and Strategies (Children born in 2009)
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Pinkfellow\" post_id=\"2040092\" time=\"1633072706\" user_id=\"137321:
Question and solution here --
Helen and Ivan had the same number of coins. Helen had a number of 50-cent coins and 64 20-cent coins. These coins had a mass of 1.134 kg. Ivan had a number of 50-cent coins and 104 20-cent coins .
(a) Who has more money in coins and by how much?(2)
(b) given that each 50-cent coin is 2.7g more heavier than a 20-cent coin, what is the mass of Ivan’s coins in kilograms? (2)
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My daughter managed to get this right but took her a while to figure it out. -
With due respect, don’t think it’s so extreme that enrichment centre is now a must. My kid is from neighbourhood school and she said she came across the Helen question before in papers, plus Teachers also guided them before
But if really there are schools where this type question has never been discussed, then it’s a problem. -
Pinkfellow\" post_id=\"2040092\" time=\"1633072706\" user_id=\"137321:
I attempted this question so here is my solution but im not sure if it is corrrect:
Helen and Ivan had the same number of coins. Helen had a number of 50-cent coins and 64 20-cent coins. These coins had a mass of 1.134 kg. Ivan had a number of 50-cent coins and 104 20-cent coins .
(a) Who has more money in coins and by how much?(2)
(b) given that each 50-cent coin is 2.7g more heavier than a 20-cent coin, what is the mass of Ivan’s coins in kilograms? (2)
let number of 50 cent coins Helen has be x
total coins of Helen = x+64(20 cent coins)
let number of 50 cent coins Ivan has be y
Total number of coins Ivan has = y+ 104 (20 cent coins)
Since both have the same number of coins
x+64 = y+104
x = y +40
Helen has 40 50 cent coins more than Ivan
(40 x 50) - (40 x 20) = 1200 cents
= 12 dollars
The answer is 12 dollars
(B)
Helen: x no. of 50 cent coins + 64 20 cent coins = 1.134kg
Ivan (has 40 less 50 cent coins and 40 more 20 cent coins)
Since total no. of coins remain the same and 50 cents coins are 2.7g heavier,
40 X 2.7 = 108g
1.134kg - 0.108 = 1.026kg
The answer is 1.026kg
Do let me know whether my working is correct -
Well, you are using algebra leh. No mark given leh.
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My daughter says easy leh. She did mention some school mates cried too but common cos she said the same students cried during all exam so nobody cared about them. So strange.
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happydaddy\" post_id=\"2040144\" time=\"1633084396\" user_id=\"5470:
Algebra is allowed, it's in the syllabus
Well, you are using algebra leh. No mark given leh. -
happydaddy\" post_id=\"2040144\" time=\"1633084396\" user_id=\"5470:
Algebra is allowed, it's in the syllabus
Well, you are using algebra leh. No mark given leh. -
happydaddy\" post_id=\"2040144\" time=\"1633084396\" user_id=\"5470:
Why no mark given ?
Well, you are using algebra leh. No mark given leh.
In Psle Maths National exam,
as long as one can use any creative method to solve Maths problem, and systematically show the steps logically step by step, marks will be awarded. Yes, inclusive of \"Algebra \" method used. Algebra method is used in Secondary schools, Sec 1 -
Pinkfellow\" post_id=\"2040092\" time=\"1633072706\" user_id=\"137321:
Explanation :
Helen and Ivan had the same number of coins. Helen had a number of 50-cent coins and 64 20-cent coins. These coins had a mass of 1.134 kg. Ivan had a number of 50-cent coins and 104 20-cent coins .
(a) Who has more money in coins and by how much?(2)
(b) given that each 50-cent coin is 2.7g more heavier than a 20-cent coin, what is the mass of Ivan’s coins in kilograms? (2)
104 - 64 = 40 (Ivan has 40 less 50 cent coins than Helen while Helen has 40 less 20 cent coins than Ivan)
M1
(0.5 - 0.2 = 0.3
a) 40 x 0.3 = 12)
M2
(0.5 x 40 = 20
0.2 x 20 = 8
a) 20 - 8 = 12)
40 x 2.7 = 108
108 g = 0.108 kg
b) 1.134 - 0.108 = 1.026
a) Helen had $12 more.
b) The mass of his coins is 1.026 kg. -
Can I check something. For the secondary posting exercise after PSLE results are out, will the secondary schools update their indicative COP (in AL terms) or do we just have to follow what’s the current indicative ALs on MOE school finder now? Thanks!
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