As long as Loren drove, the law of motion was
As long as Loid drove, the law of motion was
So, the total time they took is
Had Loren driven the whole time, the law of motion would have been
And we know that this time would have been 30 minutes (i.e. 0.5 hours) faster. So, we have
This translates into
If we subtract 200/s from both sides, we have
We can simplify the right hand side by summing the two fractions:
So, we have to solve
If we cross multiply the denominators, we have
Which yields the solutions
We accept the positive solution, because the negative would mean to travel backwards, so Loren's rate was 50mph