The last option :) Ask if explanation needed
I can see it goes through the point (2, 2)
b = 6 then
solved it the lazy way, graphically with desmos and a slider for b, see screenshot
Given:
treasury bond = 40,000
brokers commission = 600
interest rate = 12$ p.a
interest paid semi-annually, january 1 and july 1.
Since the treasury bond was sold on June 1, its interest revenue will only be equal to 1 month ( June 1 to July 1).
12% / 12 months = 1% per month
40,000 * 1% = 400 interest revenue to be recorded on July 1.
Its 41 tell me if u need step by step