How to find inverse variation - PSAT Math
Card 0 of 84
Find the inverse equation of:

Find the inverse equation of:
Tap to see back →
To solve for an inverse, we switch x and y and solve for y. Doing so yields:

To solve for an inverse, we switch x and y and solve for y. Doing so yields:
A school's tornado shelter has enough food to last 20 children for 6 days. If 24 children ended up taking shelter together, for how many fewer days will the food last?
A school's tornado shelter has enough food to last 20 children for 6 days. If 24 children ended up taking shelter together, for how many fewer days will the food last?
Tap to see back →
Because the number of days goes down as the number of children goes up, this problem type is inverse variation. We can solve this problem by the following steps:
20*6=24*x
120=24x
x=120/24
x=5
In this equation, x represents the total number of days that can be weathered by 24 students. This is down from the 6 days that 20 students could take shelter together. So the difference is 1 day less.
Because the number of days goes down as the number of children goes up, this problem type is inverse variation. We can solve this problem by the following steps:
20*6=24*x
120=24x
x=120/24
x=5
In this equation, x represents the total number of days that can be weathered by 24 students. This is down from the 6 days that 20 students could take shelter together. So the difference is 1 day less.
x y 







If
varies inversely with
, what is the value of
?
| x | y |
|---|---|
If varies inversely with
, what is the value of
?
Tap to see back →
An inverse variation is a function in the form:
or
, where
is not equal to 0.
Substitute each
in
.



Therefore, the constant of variation,
, must equal 24. If
varies inversely as
,
must equal 24. Solve for
.


An inverse variation is a function in the form: or
, where
is not equal to 0.
Substitute each in
.
Therefore, the constant of variation, , must equal 24. If
varies inversely as
,
must equal 24. Solve for
.
varies inversely with the square root of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely with the square root of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely with the square root of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute
and find
:


If varies inversely with the square root of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute and find
:
varies inversely as the square of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely as the square of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely as the square of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute
and find
:


This rounds to 3.5.
If varies inversely as the square of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute and find
:
This rounds to 3.5.
varies inversely as the cube of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely as the cube of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely as the cube of
, then, if
are the initial values of the variables and
are the final values,

Substitute
and find
:


This rounds to 2.3.
If varies inversely as the cube of
, then, if
are the initial values of the variables and
are the final values,
Substitute and find
:
This rounds to 2.3.
varies inversely as the cube root of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely as the cube root of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely as the cube root of
, then, if
are the initial values of the variables and
are the final values,
![A'\sqrt[3]{B'} = A\sqrt[3]{B}](https://vt-vtwa-assets.varsitytutors.com/vt-vtwa/uploads/formula_image/image/230538/gif.latex)
Substitute
and find
:
![A'\sqrt[3]{100} = 8\sqrt[3]{66}](https://vt-vtwa-assets.varsitytutors.com/vt-vtwa/uploads/formula_image/image/230541/gif.latex)
![A'=\frac{ 8\sqrt[3]{66}$}{\sqrt[3]{100} } \approx $\frac{ 8 \cdot 4.0412}{4.6416}$ \approx 7.0](https://vt-vtwa-assets.varsitytutors.com/vt-vtwa/uploads/formula_image/image/230542/gif.latex)
If varies inversely as the cube root of
, then, if
are the initial values of the variables and
are the final values,
Substitute and find
:
Find the inverse of
.
Find the inverse of .
Tap to see back →
To find the inverse of a function we need to first switch the
and
. Therefore,
becomes

We now solve for y by subtracting 1 from each side

From here we divide both sides by 2 which results in

To find the inverse of a function we need to first switch the and
. Therefore,
becomes
We now solve for y by subtracting 1 from each side
From here we divide both sides by 2 which results in
Find the inverse of
.
Find the inverse of .
Tap to see back →
To find the inverse we first switch the variables then solve for y.

Then we subtract
from each side

Now we divide by
to get our final answer. When we divide
by
we are left with
. When we divide
by
we are left with
. Thus resulting in:

To find the inverse we first switch the variables then solve for y.
Then we subtract from each side
Now we divide by to get our final answer. When we divide
by
we are left with
. When we divide
by
we are left with
. Thus resulting in:
Find the inverse of

Find the inverse of
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To find the inverse we first switch the x and y variables

Now we add 4 to each side

From here to isolate y we need to multiply each side by 2

By distributing the 2 we get our final solution:

To find the inverse we first switch the x and y variables
Now we add 4 to each side
From here to isolate y we need to multiply each side by 2
By distributing the 2 we get our final solution:
Find the inverse equation of
.
Find the inverse equation of .
Tap to see back →

1. Switch the
and
variables in the above equation.

2. Solve for
:





1. Switch the and
variables in the above equation.
2. Solve for :
When
,
.
When
,
.
If
varies inversely with
, what is the value of
when
?
When
,
.
When ,
.
If varies inversely with
, what is the value of
when
?
Tap to see back →
If
varies inversely with
,
.
1. Using any of the two
combinations given, solve for
:
Using
:


2. Use your new equation
and solve when
:

If varies inversely with
,
.
1. Using any of the two combinations given, solve for
:
Using :
2. Use your new equation and solve when
:
A school's tornado shelter has enough food to last 20 children for 6 days. If 24 children ended up taking shelter together, for how many fewer days will the food last?
A school's tornado shelter has enough food to last 20 children for 6 days. If 24 children ended up taking shelter together, for how many fewer days will the food last?
Tap to see back →
Because the number of days goes down as the number of children goes up, this problem type is inverse variation. We can solve this problem by the following steps:
20*6=24*x
120=24x
x=120/24
x=5
In this equation, x represents the total number of days that can be weathered by 24 students. This is down from the 6 days that 20 students could take shelter together. So the difference is 1 day less.
Because the number of days goes down as the number of children goes up, this problem type is inverse variation. We can solve this problem by the following steps:
20*6=24*x
120=24x
x=120/24
x=5
In this equation, x represents the total number of days that can be weathered by 24 students. This is down from the 6 days that 20 students could take shelter together. So the difference is 1 day less.
Find the inverse equation of:

Find the inverse equation of:
Tap to see back →
To solve for an inverse, we switch x and y and solve for y. Doing so yields:

To solve for an inverse, we switch x and y and solve for y. Doing so yields:
x y 







If
varies inversely with
, what is the value of
?
| x | y |
|---|---|
If varies inversely with
, what is the value of
?
Tap to see back →
An inverse variation is a function in the form:
or
, where
is not equal to 0.
Substitute each
in
.



Therefore, the constant of variation,
, must equal 24. If
varies inversely as
,
must equal 24. Solve for
.


An inverse variation is a function in the form: or
, where
is not equal to 0.
Substitute each in
.
Therefore, the constant of variation, , must equal 24. If
varies inversely as
,
must equal 24. Solve for
.
varies inversely with the square root of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely with the square root of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely with the square root of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute
and find
:


If varies inversely with the square root of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute and find
:
varies inversely as the square of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely as the square of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely as the square of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute
and find
:


This rounds to 3.5.
If varies inversely as the square of
, then, if
are the initial values of the variables and
are the final values,
.
Substitute and find
:
This rounds to 3.5.
varies inversely as the cube of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely as the cube of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely as the cube of
, then, if
are the initial values of the variables and
are the final values,

Substitute
and find
:


This rounds to 2.3.
If varies inversely as the cube of
, then, if
are the initial values of the variables and
are the final values,
Substitute and find
:
This rounds to 2.3.
varies inversely as the cube root of
.
If
when
, then evaluate
when
. (Nearest tenth)
varies inversely as the cube root of
.
If when
, then evaluate
when
. (Nearest tenth)
Tap to see back →
If
varies inversely as the cube root of
, then, if
are the initial values of the variables and
are the final values,
![A'\sqrt[3]{B'} = A\sqrt[3]{B}](https://vt-vtwa-assets.varsitytutors.com/vt-vtwa/uploads/formula_image/image/230538/gif.latex)
Substitute
and find
:
![A'\sqrt[3]{100} = 8\sqrt[3]{66}](https://vt-vtwa-assets.varsitytutors.com/vt-vtwa/uploads/formula_image/image/230541/gif.latex)
![A'=\frac{ 8\sqrt[3]{66}$}{\sqrt[3]{100} } \approx $\frac{ 8 \cdot 4.0412}{4.6416}$ \approx 7.0](https://vt-vtwa-assets.varsitytutors.com/vt-vtwa/uploads/formula_image/image/230542/gif.latex)
If varies inversely as the cube root of
, then, if
are the initial values of the variables and
are the final values,
Substitute and find
:
Find the inverse of
.
Find the inverse of .
Tap to see back →
To find the inverse of a function we need to first switch the
and
. Therefore,
becomes

We now solve for y by subtracting 1 from each side

From here we divide both sides by 2 which results in

To find the inverse of a function we need to first switch the and
. Therefore,
becomes
We now solve for y by subtracting 1 from each side
From here we divide both sides by 2 which results in