Answer:
ROI=17.33%
Explanation:
the rate of return = Net gain/ initial investments x 100 %
Net gains = (selling price - commissions) - purchase price
Purchase price = 20 x $30 = $600
Selling price = 710
Commission = $6
ROI ={( 710 - 6) - 600}/ 600 x 100
ROI = 104/600 x 100
ROI= 0.173333 x 100
ROI=17.33%