Question 7480
Let the distance traveled by the motorcycle be x miles.
Then the distance traveled by the walker is (25 - x) miles.

Using the distance formuls: {{{d = rt}}} Distance = rate X time, then:

{{{x = 45*t}}}  Distance traveled by the motorcycle and:
{{{(25-x) = 6*(2-t)}}} Distance traveled by the walker. 

Substitute {{{x=45*t}}} into the second equation and solve for t.

{{{(25 - 45*t) = 6*(2-t)}}}
{{{25 - 45*t = 12 - 6*t}}} Subtract 12 from both sides.
{{{13 - 45*t = -6*t}}} Add 45t to both sides.
{{{13 = 39*t}}} Divide both sides by 39.
{{{t = 13/39}}}
{{{t = 1/3}}} hours.

Now we can find how far the motor cycle traveled before conking out (breaking down).

{{{x = 45*t}}}
{{{x = 45(1/3)}}}
{{{ x = 15}}} miles.