This is the answer for your question: y=3x+130
The expression of 25t +45m shows the total number of miles driven at both speeds. In order to solve this equation you would need to know the total number of hours driven in order to multiply that by the appropriate speed in terms of miles per hour.
More information is needed to solve the problem.
Your answer would be 20.. the square root of 50 is 7.07106781187 x by 8