Answer:
1.50 h
Explanation:
For an object moving in uniform motion (= moving at cosntant velocity), the relationship between speed, distance and time is given by:
[tex]v=\frac{d}{t}[/tex]
where:
v is the speed of the object
d is the distance covered
t is the time taken to cover the distance
For this problem, we have:
d = 18 miles is the distance covered by David
[tex]v=12 mi/h[/tex] is David's speed
Therefore by re-arranging the equation, we can find the time taken by David to cover that distance:
[tex]t=\frac{d}{v}=\frac{18}{12}=1.5 h[/tex]