The 14 tooth crank gear mated to the gearbox 59 tooth gear gives a ratio of 4.21:1 which is found by 59/14.
Front sprocket 11 & rear sprocket 47 gives a ratio of 4.27:1 ie 47/11.
Overall ratio is found by multiplying the two ratios together 4.21*4.27=17.97:1
NOTE - The 14 & 59 tooth gears will be the primary gear reduction in a motorbike, this does not include the actual gearbox ratios which will need to be taken into account for the overall final ratio.