Answer:
D, 20
Explanation:
So in order to solve the equetion 2 (m/n ) (n)^ 2 we have solve the value of m interms of n in the 1st eqetion mn = 10 . so
mn = 10
m = 10/n
Now we will substitute the equetion in the expression. But befor that we have to simplify the expresion which made easy to solve.

It is equal to the expression

so we will substitute the equetion on the expresion
2(10/n)n = 20