How Many Pounds of Peanuts Selling for $5 Per Pound $\left\{ \begin{array} { l } x + y = 40 \\5 x + 8 y = 40\end{array} \right.$

Multiple Choice

How many pounds of peanuts selling for $5 per pound should be mixed with cashews selling for $8 per pound to obtain 40 pounds of mixed nuts selling for $7 per pound? Write a system of two equations in two unknowns that would model the situation. Let x = number of pounds of peanuts and y = number of pounds of cashews.

A) $\left\{ \begin{array} { l } x + y = 40 \\5 x + 8 y = 40\end{array} \right.$
B) $\left\{ \begin{array} { l } x + y = 40 \\5 x + 8 y = 280\end{array} \right.$
C) $\left\{ \begin{array} { l } x + y = 280 \\5 x + 8 y = 40\end{array} \right.$
D) $\left\{ \begin{array} { l } x + 40 = y \\5 x + 8 y = 280\end{array} \right.$