Suppose That We Model Populations (In Millions) of Predators and Preys

question 88

Multiple Choice

Suppose that we model populations (in millions) of predators and preys with the system of differential equations: $\begin{array} { l } \frac { d x } { d t } = 2 x - 1.2 x y \\\frac { d y } { d t } = - y + 0.9 x y\end{array}$ Find the expression for $\frac { d y } { d x }$ .

• A) \(\frac { 2 x - 1.2 x y } { - y + 0.9 x y }\)
• B) \(\frac { - 2 x + 1.2 x y } { - y + 0.9 x y }\)
• C) \(\frac { 2 x - 1.2 x y } { y - 0.9 x y }\)
• D) \(\frac { 2 x - 1.2 x y } { - y - 0.9 x y }\)
• E) \(\frac { y - 0.9 x y } { 2 x - 1.2 x y }\)
• F) \(\frac { - y + 0.9 x y } { 2 x - 1.2 x y }\)
• G) \(\frac { - y + 0.9 x y } { - 2 x + 1.2 x y }\)
• H) \(\frac { - y + 0.9 x y } { - 2 x - 1.2 x y }\)

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Definitions:

Quota Rent

The economic rent a producer earns from the difference between the market price of a good and its supply price due to a quota limit.

Equilibrium Price

The price at which the quantity of goods supplied is equal to the quantity of goods demanded.

Quota Price

The cost associated with acquiring a quota, which is a government-imposed limit on the quantity of a good that can be imported or exported.

Quota Rent

Revenue earned by the holder of a production or import quota, representing the market price minus the supply price under the quota limit.