SOLUTION
From the question, we are told that y varies inversely as x
This is mathematically written as

Now, we will remove the proportionality sign and replace it with equal to sign =
If we do this, we will intoduce a constant k

So we have the formula

We will substitute the values of x for 10 and y for 8 into the formula to get k, we have

Now, we will substitute k for 80 back into the formula to get the inverse function, we have

Hence the answer is option C
Answer:
0 ≤ t ≤ 5.
Step-by-step explanation:
In the function
,
is the independent variable. The domain of
is the set of all values of
that this function can accept.
In this case,
is defined in a real-life context. Hence, consider the real-life constraints on the two variables. Both time and volume should be non-negative. In other words,
.
.
The first condition is an inequality about
, which is indeed the independent variable.
However, the second condition is about
, the dependent variable of this function. It has to be rewritten as a condition about
.
.
Hence, t ≤ 5.
Combine the two inequalities to obtain the domain:
0 ≤ t ≤ 5.
To calculate percent change:
(difference between original and new)/original * 100
(19-15)/15 * 100 =
4/15 * 100 = 26.7 % increase