Answer:
8 dollars per hour
Step-by-step explanation:
If you divide 18 to 144 the answer is 8
 
        
                    
             
        
        
        
25 feet = 25 x 12 = 300 inches
First light is at 16 inches.
300 - 16 = 284 inches
Find the rest of the bulbs:
284 ÷ 4 = 71
Total number of lights = 71 + 1 = 72
Answer  72 lights