Aspeed boat is traveling at 1-- km/hr. how many hours will it take for the boat to cover a distance of 115 km? d 2.5 hours at a speed of 450 km/hr. what distance did it travel?

Velocity can be calculated using the following rule:
velocity = distance / time
therefore,
time = distance / velocity. > equation I
distance = velocity x time > equation II

Part (a):
Substitute in equation I with velocity = 1 km/hr and distance = 115 Km to get the time as follows:
time = 115 / 1 = 115 hr

Part (b):
Substitute in equation II with velocity = 450 Km/hr and time = 2.5 hr to get the distance as follows:
distance = 450 x 2.5 = 1125 km

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.