Question 1007225
.
<pre>
Mathematical model is this system of 2 equations for 2 unknowns

x + y = 210,

{{{x/60}}} + {{{y/10}}} = 6.

where x is the distance the driver covered at the speed of 60 mph, y is the distance covered at the reduced speed of 10 mph.

The system is consisted and x = 180 mi, y = 30 mi is one possible solution.
Hence, this solution is unique.

The problem is solved.
</pre>