Answer:
Yes, you should invest in the coffee roaster.
Step-by-step explanation:
Although the coffee purchase price per pound will remain the same, but the fact the aroma of roasting coffee will improve the ambience of your cafe and is apt to attract more customers implies that unit of sales or rate of sales turnover will rise.
As the units of sales increase, each additional unit sold will add to profit, given that the coffee purchase price per pound remains the same, and this will lead to an increase in total profit which is the major aim of being in business.