Answer:
The length of Track S is 2 miles.
Explanation:
Let the length of track S be s miles and, of T, be t miles.
Then we have the system:
3s + 4t = 12........ A
s + 6t = 11.............B Multiply this equation by -3:
-3s - 18t = -33
Adding this last equation to equation A:
0 - 14t = -21
t = -21/-14
t = 1.5
Now substitute for t in equation B:
s + 6 *1.5 = 11
s + 9 = 11
s = 2.