Answer: 7 years
Step-by-step explanation:
year 1 Â Â 5.75 (million) x 1.16 (16 percent ) = 6.67 Â motorcycles
year 2 Â Â 6.67 Â x 1.16 = 7.7372
year 3   7.74 x  1.16 = 8.9784
year 4 Â Â Â 8.98 x 1.16 = 10.4168
year 5   10.42 x  1.16 = 12.0834
year 6 Â Â 12.09 x 1.16 = 14.0244
year 7 Â Â 14.02 x 1.16 = 16.2632
year 1 Â Â 3.5 (million) x 1.25 (25 percent) = 4.375
year 2 Â Â 4.375 x 1.25 = 5.46875
year 3   5.47  x  1.25 = 6.8359
year 4 Â Â 6.84 Â x 1.25 = 8.5449
year 5 Â Â Â 8.55 x 1.25 = 10.6875
year 6 Â Â 10.69 x 1.25 = 13.359375
year 7 Â Â 13.36 x 1.25 = 16.7