8.42%
Using your financial calculator, input the initial cost of $142,000 as a cash outflow (negative), and each of the four cash inflows (positive) as $41,650 for each of the first 3 years and $49,000 in the fourth year. Then hit the IRR button on your financial calculator to compute the internal rate of return (IRR), as 8.4167, rounded to 8.42%.