Question 1005428
The question asks for your answer in kilometers per hour.

kilometers per hour can also be written as 

kilometers/hour

now replace kilometers with the given value of kilometers and the hours with the given value of hours

but, since the given value of hours isn't completely in hours we have to convert it.

a way to do this is to take the extra minutes and divide them by 60. this will give you the equivalent of 9 minutes in hours.

9/60 = .15

now we add .15 hours to our original 4 hours and plug it into the equation we made before.
4+.15 = 4.15 

18/4.15 = km/h

thus 4.337km/h is your answer.