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secondary 4 | E Maths
2 Answers Below
Anyone can contribute an answer, even non-tutors.
Thanks in advance
Date Posted: 4 years ago
Views: 508
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First part
Let me know if you need more explanation
Let me know if you need more explanation
Date Posted:
4 years ago
Hi Eric, thanks for the answer. I don't understand the first part though, on why it is 400><
y starts out as “its own value” of 100%.
(Starting values are always assigned to be 100%, so if let’s say you start out having $500, then $500 represents 100% of your money)
At the end, y is to be increased “BY 300%”, not “TO 300%”. This means that 100% is being increased to 400%, since there is an increase in percentage points by 300%.
Hence, the final value of y is 4 times the starting value of y. We will need to use this to solve the question for the change in x.
(Starting values are always assigned to be 100%, so if let’s say you start out having $500, then $500 represents 100% of your money)
At the end, y is to be increased “BY 300%”, not “TO 300%”. This means that 100% is being increased to 400%, since there is an increase in percentage points by 300%.
Hence, the final value of y is 4 times the starting value of y. We will need to use this to solve the question for the change in x.
Is it like model method, where y is one box, then 300% is like saying, increase by 3 times?
In this case you are not given any value whatsoever for y and x, so this question becomes rather challenging and we have no choice but to express the answer as such.
These type of questions are very hard to understand and I believe that a large proportion of all students will get stuck at such questions.
These type of questions are very hard to understand and I believe that a large proportion of all students will get stuck at such questions.
Yes! You got it.
y is like 1 unit.
An increase in 300% means an increase in 3 units.
So the final will be 400%, or 4 units.
y is like 1 unit.
An increase in 300% means an increase in 3 units.
So the final will be 400%, or 4 units.
You start out with $10. That’s 100% at the start.
If your money increases by 100%, it means your money has increased by $10, for a new sum of $20.
If instead your money increases by 500%, it means your money has increased by $50, for a new sum of $60.
If your money increases by 100%, it means your money has increased by $10, for a new sum of $20.
If instead your money increases by 500%, it means your money has increased by $50, for a new sum of $60.
Thank you!:D
An alternative phrasing of such questions is
Find the percentage decrease in x if the value of y is quadrupled.
Sometimes they will mention the numerical number to multiply, rather than a percentage number to multiply.
Find the percentage decrease in x if the value of y is quadrupled.
Sometimes they will mention the numerical number to multiply, rather than a percentage number to multiply.
Thank you!
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Second one
For this one, we try to make logical sense of the men, the percentage of the project completed and the number of days taken.
The more the number of men, the larger the percentage of the project completed for the same number of days.
So “men” is in direct proportion with the “percentage of project”.
The more the number of men, the less time needed to complete the same amount of the project.
So “men” is in inverse proportion with the “number of days”.
By the same analogy, with a fixed number of men, a larger percentage of the project can be completed given more time, so “percentage of project” is in direct proportion with the “number of days”.
For this one, we try to make logical sense of the men, the percentage of the project completed and the number of days taken.
The more the number of men, the larger the percentage of the project completed for the same number of days.
So “men” is in direct proportion with the “percentage of project”.
The more the number of men, the less time needed to complete the same amount of the project.
So “men” is in inverse proportion with the “number of days”.
By the same analogy, with a fixed number of men, a larger percentage of the project can be completed given more time, so “percentage of project” is in direct proportion with the “number of days”.
Date Posted:
4 years ago
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