Answer:
6 hours
Explanation:
The entire trip is 400 miles.
100 miles divided by 400 miles is 100/400 = 1/4.
100 miles is 1/4 of the trip.
400 miles - 100 miles = 300 miles
She still has to drive another 300 miles. 300 miles is 3 times the distance she already drove.
Since it took her 2 hours to drive 100 miles, it will take her 3 times that time to drive 3 times the distance.
3 * 2 hours = 6 hours
Answer: 6 hours