Can you show me how to calculate IRR? whats the difference between IRR and incremental IRR?

Betas Internal Rate of Return (IRR) (second decimal; no rounding) is a) 13.35%; b) 14.55%; c) 15.22; d) 15.39%. 17. Gammas Internal Rate of Return (IRR) (second decimal; no rounding) is a) 12.88%; b) 13.17%; c) 13.64%; d) 14.06%. 18. The incremental Internal Rate of Return (IRR) between Alpha and Gamma (second decimal; no rounding) is a) 10.95%; b) 11.29%; c) 11.68%; d) 11.87%.

A company is considering the purchase of a new truck for its expanding landscaping business. The key parameters of the three trucks under scrutiny (Alpha, Beta and Gamma) are provided below. Alpha Gamma 800,000 increasing by thereafter Beta Parameters 600,000 increasing by 3% thereafter 750,000 300,000 at EOY1 450,000 at EOY1 430,000 at EOY1 decreasing by 1. Initial Cost (S) annually 2%annually | 2,000 annually ! 2. Revenues ($) thereafter 130,000 at EOY1 255,000 at EOY1in by increasing by 1,000 annually thereafter increasing by increasing by 2% annually thereafter 8. operating COsts5.000 annually 4. End-of-life salvage 5. Useful life (years) thereafter. 15,000 10,000 5,000 10 value ($ Industry Standard 4 years MARR-10% 1 Alpha's Net Future Worth (NFW) after 5 years (rounded to the nearest $100) is a) $99,600; b) $116,900; c) $125,400; d) $133,600 2. Beta's NFW after 10 years (rounded to the nearest $100) is a) $285,100; b) $325,200; c) $388,900; d) $394,100 3. Gamma's Net Present Worth (NPW) (rounded to the nearest $100) is a) $133,400; b) $136,900; c) $146,900; d) $172,500. Alpha's Annual Equivalent Worth (AEW) (rounded to the nearest $100) is a) $21,900; b) $23,300; c) $23,400; d) $24,300 4. 5. Beta's Annual Equivalent Worth (AEW) (rounded to the nearest $100) over 20 years (it was repeated several times) is a) $18,800; b) $19,000, c) $19,100, d) $20,400 6 The best truck based on the NPW method is a) Alpha, b) Beta, c) Gamma. 7. Based on the simple payback method, Gamma's recovery period (to the nearest half or full year) is