Answer:
150 miles
distance travelled on the third day = 150 miles
Explanation:
Note: it was given that they drove the same speed throughout the trip. That means their speed is constant for all days;
For the first day
distance = 300 miles
time = 6 hours
Speed = distance/time
Speed = 300/6 = 50 mph
on the third day;
time = 3 hours
Speed = speed on first day = 50 mph
distance = speed × time
distance = 50 mph × 3 hours
distance = 150 miles
distance travelled on the third day = 150 miles