please help me with the last three questions

The expected average rate of return for a proposed investment of $502,300 in a fixed asset with a useful life of 4 years, straight-line depreciation, no residual value, and an expected total income of $169,640 for the 4 years is (round to two decimal places) a, 8.44% b. 0.68% Oc. 0.34% Cd. 16.89% Hayden Company is considering the acquisition of a machine that costs $463,000. The machine is expected to have a useful life of 6 years, a negligible residual value, an annual net cash inflow of $86,000, and annual operating income of $73,100. The estimated cash payback period for the machine is (round to one decimal place) Ca. 7.5 years Ob. 63 years Oc. 54 years Od. 12 years Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $49,100 Training of machine operators 25,000 Processing returned products 16,800 Scrap processing (disposal) 25,000 Rework 8,100 Preventative maintenance 31,400 Product design 43,300 Warranty work 7,000 Finished goods inspection 23,000 From the provided schedule of activity costs, determine the total activity cost. a. $149,300 b. $276,727) c. $228,700 d. $99,000