let

v1 = the speed of Jack

v2 = the speed of Mather

t = the time

Jacks speed is 10 mph faster than Mathews:

v1 = 10 + v2

since speed = distance/time we have time = distance/speed

Jack can drive 225 miles in the same time that Mather can drive 195 miles:

225/v1 = 195/v2

plug v1 = 10 + v2 into the last equation:

225/(10 + v2) = 195/v2

by solving we find:

v2 = 65 mph

click here to see the step by step solution of the equation:

v1 = 10 + 65

v1 = 75 mph

Jack's speed is 75 mph.

Mathew's speed is 65 mph.