What is the concentration of the ferric nitrate after mixing?

Assume that the volume of solution is additive.

After mixing:
Volume of the mixture = (45.00 + 30.00) mL = 75.00 mL
Concentration of ferric nitrate = 0.00150 × (45.00/75.00) M = 0.000900 M

Sorry, my answer is "Anonymous" as your post is Anonymous. There is no need for an Anonymous question in this category, Most 'Anonymous' posts are trolls, maybe yours is not, but the high likelihood is there. If you post as yourself, I would be glad to help you with any problem you have.
I spend a lot of time on each problem, I just want to make sure it's for a worthwhile cause.