Firm E has net income of 75,000 sales of 1,250,000 and ROI 15% Calculate the firm's turnover and average total asset

With the given net income amount, and the ROI percentage, you can derive total assets.

Then, with the assets amount and sales amount in hand, you can determine turnover.

Both of those ratios are found in your book or in the question's background material. Check back in if you're still unsure.