Answer:
50 mph
Explanation:
drive to reach their grandmother's house in 4 hours
Given that:
Miles driven = 550 miles
Miles already driven = 350 miles
Miles left to drive = (550 - 350) miles = 200 miles
To reach destination in 4 hours
Speed in miles per hour will be :
Distance / time
= 200 miles / 4 hours
= 50 miles / hour