Answer:
74 mph
Step-by-step explanation:
step 1
Find the total time
A sailboat started his journey at 6:30 am and reached his destination at 11:45 pm
so
from 6:30 am to 12:00 pm ----> there are 5 hours + 30 minutes=5.5 hours
from 12:00 pm to 11:45 pm ----> there are 11 hours + 45 minutes=11.75 hours
The total time is
5.5+11.75=17.25 hours
step 2
Find the average speed
we know that
The average speed is equal to divide the total distance by the total time

 
        
             
        
        
        
If the rectangle has a fixed width of 300, it means that

where  and
 and  are width and length, respetively.
 are width and length, respetively.
So given the length  , the are would be
, the are would be

 
        
             
        
        
        
19-13p=-17p-5
+5                +5
24-13p=-17p
   +13p   +13p
24=-4p
/-4   /-4
-6=p
        
                    
             
        
        
        
Any number less than or equal to 12