What is return on investment in marketing?

ROI regers to return on investment this means that how much money you spent and what is amount you got back with your investment
Return on investment or return on costs is a ratio between net income and investment
Generally ROI is used to measure the efficiency and effectiveness of the investment, it tells us that whether the investment was good or bad.Return on investment (ROI) is a performance measure used to evaluate the efficiency or profitability of an investment or compare the efficiency of a number of different investments
increased revenue/ money you spent on marketing* 100