25 mi/h means 25 miles per hour, which means it would take you 1 hour to go 25 miles.
This can be represented in a ratio of hours to miles.
hours:miles
1:25
If miles are 200, then the ratio would be x:200
Divide 200 by 25 to see how much the miles were multiplied by to get 25, then multiply 1 (hours) by that number to get the answer, since both sides must have the same done to them.
200 / 25 = 8
So 25 • 8 = 200, meaning 1 • 8 = 8, and the answer is 8 hours.
Original ratio: 1 hour:25 miles
New ratio: 8 hours:200 miles