Bpp revision kit question 276

Dear Sir, Box Co has an operating profit of $20,000 and operating assets of $95000. the cost of capital is 12%. there is a proposed investment of $10000 which will increase the operating profit by $1400. what is the RI with the proposed investment? I thought the answer was $8800 but the solution shows depreciation of $850 so the answer is $7950? I cant find where the depreciation figure came from. looking forward to hearing from you. Best regards.