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Primary 5
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Number and Algebra
Making it visual...
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1
Lkc Lim
Thanks!
6 years ago
Candy Loh
Asked 9 years ago
SG
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Primary 5
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Number and Algebra
Pls help again! Thanks40% of Cindy's money is 80% of Rachel's money. If Rachel has $100, how much money does Cindy have?
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Shaoyang Brandon
Hi, Candy! Refer to the solution below. What challenges did you have with the question? :)
6 years ago
Candy Loh
My kid dun understand the question. Thanks
6 years ago
Jason Oon
1.
40% of Cindy's money is 80% of Rachel's money means that Cindy has more money.
2.
40% Cindy -> 80% Rachel
10% Cindy -> 20% Rachel
100% Cindy -> 200% Rachel
$100 x 2 = $200
6 years ago
BA Poh Ann
Suggestion:
Change % to fraction,
40% = 2/5 (C)
80% = 4/5 (R)
Since 40% of C = 80% of R,
2/5 (C) = 4/5 (R)
Find the common multiple of their numerators:
4/10 (C) = 4/5 (R)
Denominators represent their units,
Cindy = 10 units, Rachel = 5 units
5 units = $100
10 units = 2 x $100 = $200 (Ans)
6 years ago
Lkc Lim
Asked 9 years ago
SG
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Primary 5
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Number and Algebra
Can anyone help? Thanks!
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Yeo See Yeong
3 double seats for 180 mins. technically can house 6*180 = 1080 people (each for 1 min). since each person rowed 135min, there are 1080/135 = 8 people.
6 years ago
Lkc Lim
Thanks but explain this way my niece will be blur lol
6 years ago
Candy Loh
Asked 9 years ago
SG
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Primary 5
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Number and Algebra
Hi. Here is the solution. What challenges did you have with the question? :)
6 years ago
Josephine Koh
Find that this is a difficult Qn.😀 why for x we need to add 6 and 5? And why zizi part is 5+1=6? Thanks?
6 years ago
Shaoyang Brandon
No need to add 5 and 6 for Xavier. The numbers are the differences for the various comparisons of the 3 of them.
For Zizi, because Yathi gave away one unit to Xavier, Yathi has 6 units instead of 5 units lesser than Zizi.
The difficult part is to partition the big units into smaller units. :) Partitioning, for me, is always more challenging because you have to fit in the information seamlessly. Do you also have this challenge too? :)
6 years ago
Josephine Koh
Thanks. But still can't get that 1 unit is $14. How about the 25? Do we need to use that? Thanks!
6 years ago
Shaoyang Brandon
Do you see the dark blue lines that extend slightly out of the model? That was the initial size of the unit when I saw that X was 3/5 of Y. So, it was 3 BIG UNITS FOR X, 5 BIG UNITS FOR Y. :)
Then, because Y is 3/4 of Z, I had to find a way to change THE 5 BIG UNITS OF Y INTO MULTIPLES OF 3 SO THAT Y IS 3/4 OF Z.
Thus, I cut the BIG UNIT marked by the thick blue lines INTO 3 SMALLER UNITS. Y is now 3/4 of Z.
Then, I observed that X HAS 9 UNITS AND Y HAS 15 UNITS. If I moved 1 UNIT FROM Y TO X, then,
X HAS 9+1 = 10 UNITS AND Y HAS 15-1=14 UNITS.
X is now 10/14 (or 5/7) of Y. That was how I know that the 1 smaller unit is $14. :)
6 years ago
Shaoyang Brandon
I suddenly realised I made an error. It should be $25, not $14. Sorry for the error.
Otherwise, everything else is in place. :)
6 years ago
Josephine Koh
Thank you for your solution!!😀
6 years ago
Yeo See Yeong
6 years ago
Josephine Koh
Thank you for the solution!!😀
6 years ago
Josephine Koh
Thanks. But still can't get that 1 unit is $14. How about the 25? Do we need to use that? Thanks!
6 years ago
Shaoyang Brandon
Do you see the dark blue lines that extend slightly out of the model? That was the initial size of the unit when I saw that X was 3/5 of Y. So, it was 3 BIG UNITS FOR X, 5 BIG UNITS FOR Y. :)
Then, because Y is 3/4 of Z, I had to find a way to change THE 5 BIG UNITS OF Y INTO MULTIPLES OF 3 SO THAT Y IS 3/4 OF Z.
Thus, I cut the BIG UNIT marked by the thick blue lines INTO 3 SMALLER UNITS. Y is now 3/4 of Z.
Then, I observed that X HAS 9 UNITS AND Y HAS 15 UNITS. If I moved 1 UNIT FROM Y TO X, then,
X HAS 9+1 = 10 UNITS AND Y HAS 15-1=14 UNITS.
X is now 10/14 (or 5/7) of Y. That was how I know that the 1 smaller unit is $14. :)
6 years ago
Shaoyang Brandon
I suddenly realised I made an error. It should be $25, not $14. Sorry for the error.
Otherwise, everything else is in place. :)