A tractor whose weight is 20 tonnes has a drawbar pull of 2500 kg, when operated on a level road having a rolling resistance of 30 kg per tonne. If this tractor is operated on a level road having a rolling resistance of 40 kg per tonne, then the drawbar pull of the tractor will

A. 9 days B. 13 days C. 14 days D. 19 days

A. $$\frac{{{{\text{t}}_{\text{o}}} + 3{{\text{t}}_{\text{m}}} + {{\text{t}}_{\text{p}}}}}{2}$$ B. $$\frac{{{{\text{t}}_{\text{o}}} + 3{{\text{t}}_{\text{m}}} + {{\text{t}}_{\text{p}}}}}{3}$$ C. $$\frac{{{{\text{t}}_{\text{o}}} + 4{{\text{t}}_{\text{m}}} + {{\text{t}}_{\text{p}}}}}{4}$$ D. $$\frac{{{{\text{t}}_{\text{o}}} + 4{{\text{t}}_{\text{m}}} + {{\text{t}}_{\text{p}}}}}{5}$$ E. $$\frac{{{{\text{t}}_{\text{o}}} + 4{{\text{t}}_{\text{m}}} + {{\text{t}}_{\text{p}}}}}{6}$$

A. Number of operations B. Output of labour C. Output of machinery D. All the above

A. 3.5 and $$\frac{5}{6}$$ B. 5 and $$\frac{{25}}{{36}}$$ C. 3.5 and $$\frac{{25}}{{36}}$$ D. 4 and $$\frac{5}{6}$$