First method: by the rule of three:
126 miles---------------------3 hours
x---------------------------------7 hours
x=(126 miles * 7 hours) / 3 hours=294 miles.
Answer: 294 miles.
Second method:
Speed=distance/ time ⇒distance=speed x time
We calculate the speed of the car:
Speed=126 miles/3 hours= 42 miles/hour.
Data:
Speed=42 miles/hour
time=7 hours
Distance=speed x time
Distance=(42 miles/hour)(7 hours)=294 miles
answer: 294 miles.