Answer:
See below
Explanation:
The question is missing information: " . . . how far would he go in an ???"
If the question is how far he would go in a [Pick a despised car model} ? The answer is still 400. The car would break down.
If the question is how far would he go in the same amount of time:
Whe the speed limit was 55, it would take Bob (55 miles/hr)*(X hr) = 400 miles
X = 7.273 hours to go 400 miles at 55 mph.
A speed limit of 70 mph would allow Bob the go:
(70 miles/hour)*(7.272 hours) = 509.1 miles