For positive real numbers x and y,
$$\begin{aligned} x \cdot y & = 5 \\ x ^ { 2 } + y ^ { 2 } & = 15 \end{aligned}$$
Given this, what is the value of the expression $x ^ { 3 } + y ^ { 3 }$?
A) 40
B) 45
C) 50
D) 60
E) 75
For positive real numbers x and y,

$$\begin{aligned}
x \cdot y & = 5 \\
x ^ { 2 } + y ^ { 2 } & = 15
\end{aligned}$$

Given this, what is the value of the expression $x ^ { 3 } + y ^ { 3 }$?

A) 40\\
B) 45\\
C) 50\\
D) 60\\
E) 75