Answer:
This is an inverse variation, and the constant of variation is k = 2.
Step-by-step explanation:
Direct variation is something like:
y = k*x
Where k is the constant of variation.
So as x increases also increases y.
Inverse variation is something like:
y = k/x
k is the constant of variation.
In this case, if x increases, y decreases.
Now let's look at the equation:
-10 + 15*x*y = 20
Let's isolate y in one side of the equation:
15*x*y = 20 + 10 = 30
15*x*y = 30
y = 30/(15*x) = (30/15)/x = 2/x
y = 2/x
Then we can conclude that this is an inverse variation, with a constant of variation equal to 2.
You have to add 2.52 and 1.26 and divide it by 18!
I'm sure it will be <span>57.42 pound</span>
Inverse variation means y=k/x (direct variation is y=kx) so we can use the info given to find the constant k
y=k/x
6=k/900
k=6(900)
k=5400 so the equation is:
y=5400/x or more accurately for this problem
t(v)=5400/v then:
t(800)=5400/800
t(800)=6.75 hours