问道我很纠结的数学题

unicornheart

关于碳排放的
给个表：           Avg. #/Day(000s) ; avg. distance travelled by one vehicle/day (km); avg. # of seats; avg. occupancy (%); avg CO2 emission (gram/person/km)
           Motorcycle:           320                                      26                                                          1.6                        71                                    75
           Car            :          1075                                     43                                                          4.3                       33                                     250
note: 1 tonne = 1000kg
refers to avg. CO2 emission for a vehicle with avg. occupancy

Question:
if CO2 emissions were taxed at $100 a tonne, approximately how much tax would a lone car driver save every month, based on avg. emission figures, if he switched to motorcycling (alone) 15 kms to work and back, 22 days a month?
A. $10  B. $12  C. $14  D. $16  E$18

选E

还有一问
encourages people to car-share. assuming emissions per vehicle remain unchanged, approximately what should the avg. occupancy of motor cars be for CO2 emissions per person, to equal those from trains?
A. 40% B. 50% C. 60% D. 70% E. 80%

觉得好乱，想不明白啊，求NN解答

unicornheart

up