Answer:
Step-by-step explanation:
A direct variation equation is of the form
y = kx,
where, in words, it reads "y varies directly with x" or "y varies directly as x". In order to use this as a model, we have to have enough information to solve for k, the constant of variation. The constant of variation is kind of like the slope in a straight line. It rises or falls at a steady level; it is the rate of change.
We have that a vet gives a dose of three-fifths mg to a 30 pound dog. If the dose varies directly with the weight of the dog, then our equation is
d = kw and we need to find k in order to have the model for dosing the animals.

Divide both sides by 1/30 to get k alone.
and

Our model then is

This means that for every pound of weight, the dog will get one-fiftieth of a mg of medicine.
Answer:
The possible numbers of songs that you can burn onto the CD is 11.
Step-by-step explanation:
The total storage capacity of CD = 70 minutes
Storage already used = 25 minutes
Hence, The available storage = Total available storage - Used Storage
= 70 minutes - 25 minutes = 45 minutes
Hence, the CD has 45 minutes storage left.
Now, each song takes up 4 minutes of storage.
⇒ 
= 
⇒The number of songs possible = 11.25 ≈ 11
Hence, the possible numbers of songs that you can burn onto the CD is 11.
The first statement is correct.
F(3) = $4 + $2.5(3)
f(3) = $4 + $7.5
f(3) = $11.50