A reverted gear train has gear 1 (T_{1} = 10) driving gear 2 (T_{2} = 20); gear 3 (T_{3} = 32) is on the same shaft as gear 2 and drives gear 4 (T_{4} = 40), which is co-axial with gear 1. Find the speed ratio N_{1}/N_{4}. (dimensionless) The two gear pairs have different modules, chosen so that gears 1 and 4 are co-axial.