Check my work 4 Gibson Corporation's balance sheet indicates that the company has $580,000 invested in operating assets. During 2018, Gibson earned operating income of $67,280 on $1160,000 of sales. Required a. Compute Gibson's profit margin for 2018. 10 points b. Compute Gibson's turnover for 2018 02:10:13c. Compute Gibson's return on investment for 2018. d. Recompute Gibson's ROl under each of the following independent assumptions: (1) Sales increase from $1,160,000 to $1,392,000, thereby resulting in an increase in operating income from $67,280 to $76,560. eBook Print References (2) Sales remain constant, but Gibson reduces expenses, resulting in an increase in operating income from $67,280 to $69,600. (3) Gibson is able to reduce its invested capital from $580,000 to $464,000 without affecting operating income. Complete this question by entering your answers in the tabs below Req A to C Req D Compute Gibson's profit margin, turnover and return on investment for 2018. (Round "Profit margin" and "Return on investment" to 1 decimal place.) a. Profit margin b. Turnover times