Astrophysics question (Star Magnitude)

[Scripturient]

Homework Statement:

Suppose that to a particular heliocentric 3D-Cartesian coordinate, the Earth is located at (1,0,0) A.U. You tried to observe Nanyang Star (with the same luminosity as the Sun) from the Earth. Nanyang Star is located at (1,0,1) kpc in the same coordinate system. If you obtained a visual magnitude of +17.2 from the observation, what is the coefficient of absorption, defined as the visual magnitude increase per unit distance due to interstellar matter, in the star’s direction? (It is given that Sun’s absolute magnitude is +4.83.)

Relevant Equations:

Apparent Magnitude

My attempt has been attached.

 

[mjc123]

Shouldn't you have m₂ - m₁ = 5log(d₂/d₁) + Ad₂?
And is d₂ = 1000 pc?

 

[phyzguy]

As @mjc123 implied, you don't have d specified correctly. How far is it from Earth to Nanyang's star in pc? This is what you should use for d.