please answer correctly! ive put on chegg twice and still wrong, will rate! thank you

Feather Friends, Incorporated, distributes o high-qualify wooden birdhouse that sells for $120 per unit Variable expenses are $6000 per unit, and fixed expenses total $180,000 per year. its operating results for last year were as follows: The president does not want to change the seling price. Instiead, he wants to increase the sales commission by 52.10 per unit He thinks that this move, combined with some increase in advertising, would increase this year's unit sales by 25%. Hod much could the president increase this year's advertising expense and stil earn the same $1,380,000 net operating income as last year? ( Oo not round intermediate calculations.)