To solve the set of equations given above, we can use the substitution method where we substitute one equation to the other and solving for one variable. We do as follows:
0.4x - 0.1y = 2
x = 5 + 0.25y
0.2x + 0.5y = 1
0.2(5 + 0.25y)+ 0.5y = 1
y = 0
x = 5
Therefore, the correct answer from the choices is option A, (5,0).