You use 1 step equation to find out the answer
I am not 100% sure this is right but I believe its 28:)
In order to find b1 from your formula stated we need to do few calculations
A=hb1+hb2, as you wee I multiply h with both bases( b1 and b2)
I will subtract hb2 from both sides
hb1=A-hb2
now I will divide my new expression by h
b1=(A-hb2)/h
He bought last year and year later total is $104.3
Each share he sold 62.80 with tax is 0.03
62.80x1.03= $64.684 for each share
So there are 40 shares
64.684 x 40= $2587.36