Question 102480
Let t = the time in hours that it takes to fly to St. Paul at 250mph.
Since it takes 1 hour longer to fly there at 200mph, this will = t+1.

We know the distance to and from St. Paul is the same, so we can represent this distance two ways:

Distance = speed * time
D = 250t
and
D = 200(t+1)

Since the two distances are equal, we can now plug the first formula into the second one and get an equation with one variable.

250t = 200(t+1)
First use the distributive property on the right side of the equation.
250t = 200t + 200
Subtract 200t from each side of the equation.
50t = 200
Divide each side of the equation by 50.
t = 4

Now we know the time it takes to travel to St. Paul at 250mph is 4 hours.

Next, we plug that into the equation for distance.
D = 250t
D = 250 * 4
D = 1000

St. Paul is 1000 miles away.

We can check to make sure we got the right answer by using our second equation for distance.

D = 200(t+1)
D = 200 * (4+1)
D = 200 * 5
D = 1000

Our answer checks out. That's all for this problem.