Find the percentage increase in y

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In summary, the conversation discusses the relationship between y and x, where y is directly proportional to x2. The participants then go on to discuss the impact of increasing x by 100% on y, with one participant providing a calculation to determine the percentage increase in y. However, there is a discrepancy regarding the value of x after the increase, with one participant stating it should be 2x while another argues it should be 4x.
  • #1
topsyturvy
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y is directly proportional to x2.
x is increased by 100%.
Find the percentage increase in y.

so,
y=k x2

y= k (100 + x2)
then i went to find the k,
which is
k= y/ (100 + x2)

so i put back the k which i found into y= k (100 + x2)
which is :
y= y/(100 + x2) (100 + x2)

them I am stuck here..
somebody pls helppp!
thanks lotsa.:smile:
 
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  • #2
it should be [tex] 4x^{2} [/tex] not [tex] x^{2} + 100 [/tex]
 
Last edited:
  • #3
topsyturvy said:
y is directly proportional to x2.
x is increased by 100%.
...
y= k (100 + x2)
x is increased by 100% just means that x has been doubled (i.e: 2x), and not 100 + x. Do you see why?
Consider the original amount (say b) to be 100%, so when increasing the original amount (i.e increase b) by 100% means that you add one more b to your original b, and get 2b, right?
So, can you go from here? :)
-------------
@courtrigrad: No, it should be 4x2, not 2x2. :smile:
EDIT: He did edit the post. Cheers. :)
 
Last edited:

Related to Find the percentage increase in y

1. What is the formula for finding the percentage increase in y?

The formula for finding the percentage increase in y is: (New y - Old y) / Old y * 100

2. How do you interpret the percentage increase in y?

The percentage increase in y represents the amount by which y has increased in comparison to its previous value. It is expressed as a percentage of the original value.

3. Can the percentage increase in y be negative?

Yes, the percentage increase in y can be negative if the new y value is less than the old y value. This indicates a decrease in y.

4. Is there a difference between percentage increase and absolute increase?

Yes, percentage increase and absolute increase are two different measures. Percentage increase is a relative measure, while absolute increase is an absolute measure. Percentage increase takes into account the original value, while absolute increase does not.

5. How is finding the percentage increase in y useful?

Finding the percentage increase in y can be useful in many situations, such as analyzing sales data, tracking stock market performance, or evaluating changes in population. It allows us to compare the magnitude of change in y over time and make informed decisions based on that information.

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