I think there is a mistake in the calculation of e-Imer
his Formula: (.2m/m) * (900 kg)*(9.8 (m/(s^2)))*(40(km / s)) = 70,560kW
I think v has to be taken in m/s (40km/h means 11,11m/s); (.2m/m) * (900 kg)*(9.8 (m/(s^2)))*(11m / s)) = 19,8kw
But I am not sure, if Naveen realy wants to drive with 40km/h even on 20% grade.
If the 40/45km/h is for flat area and on 20% grade less than 20 km/h is fine, the 10kW motor would fit (the peak for this motor is anyway 20kW)