One week, 72 people got a speeding ticket. The next week, only 36 people got a speeding ticket. What a the percent of change in
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Answer:
if and
.
Step-by-step explanation:
We are given and
.
We are asked to find .
means
You only have one pair of like terms, that is the constants.
Answer:
or
(depending on your teacher's format preference)
Step-by-step explanation:
<h3><u>Proportionality background</u></h3>Proportionality is sometimes called "variation". (ex. " 'y' varies inversely as 'x' ")
There are two main types of proportionality/variation:
- Direct
- Inverse.
Every proportionality, regardless of whether it is direct or inverse, will have a constant of proportionality (I'm going to call it "k").
Below are several different examples of both types of proportionality, and how they might be stated in words:
y is directly proportional to x
y is directly proportional to x squared
y is directly proportional to x cubed
y is directly proportional to the square root of x
y is inversely proportional to x
y is inversely proportional to x squared
From these examples, we see that two things:
- things that are <u>directly proportional</u> -- the thing is <u>multipli</u>ed to the constant of proportionality "k"
- things that are <u>inversely proportional</u> -- the thing is <u>divide</u>d from the constant of proportionality "k".
In our question, y is inversely proportional to x, so the equation we're looking at is the following .
It isn't yet clear what the constant of proportionality "k" is for this situation, but we are given enough information to solve for it: "When y=12, x=5."
We can substitute this known relationship pair, and find the "k" that relates this pair of numbers:
<h3><u>Solving for k, and finding the general equation</u></h3>General Inverse variation equation...
Substituting known values...
Multiplying both sides by 5...
Simplifying/arithmetic...
So, for our situation, k=60. So the inverse proportionality relationship equation for this situation is .
The way your question is phrased, they may prefer the form: