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