Why is it 10%

Ripe Vines Winery is considering the purchase of a state-of-the-art bottling machine. The new machine will cost $20,790 and will have a useful life of 4 years. The new machine will provide net cash savings of $6,000 per year. What is the internal rate of return (IRR) for the new bottling machine? 8% 0.794 0.735 0.681 0.630 0.583 0.540 0.500 0.463 10% 0.751 0.683 0.621 0.564 0.513 0.467 0.424 12% 0.712 0.636 0.567 0.507 0.452 0.404 0.361 0.322 14% 0.675 0.592 0.519 0.456 0.400 0.351 0.308 0.270 0.386 Present Value of $1 Periods 6% 3 0.840 4 0.792 5 0.747 6 0.705 7 0.665 8 0.627 9 0.592 10 0.558 Present Value of Annuity of $1 Periods 6% 3 2.673 4 3.465 5 4.212 6 4.917 7 5.582 8 6.210 9 6.802 10 7.360 8% 2.577 3.312 3.993 4.623 5.206 5.747 6.247 6.710 10% 2.487 3.170 3.791 4.355 4.868 5.335 5.759 6.145 12% 2.402 3.037 3.605 4.111 4.564 4.968 5.328 5.650 14% 2.322 2.914 3.433 3.889 4.288 4.639 4.946 5.216 A 10% . 14% XO OC. 6% OD. 8%