Repeat the previous problem supposing that the brokerage fee is quoted as 0.3% of the bid or

Question:

Repeat the previous problem supposing that the brokerage fee is quoted as 0.3% of the bid or ask price.
a. What amount will you pay to buy 100 shares?
b. What amount will you receive for selling 100 shares?
c. Suppose you buy 100 shares, then immediately sell 100 shares with the bid and ask prices being the same in both cases. What is your round-trip transaction cost?