40,000 mph =64,373.76 km/h
Distance to Pluto =~7.5 x 10^9 km.
[7.5 x 10^9] / 64,373.76 =~116,507 hours /24 hours =~4,854 days/365.25 days =~13 years.
But only if the two planets were stationary. However, NASA's spacecraft "New Horizons", took it about 10 years and 10 months due to the orbit of Pluto being the closest to us at that time.
