According to the problem, Leslie will need to drive 850. As she is driving at a constant speed of 65 miles per hour, if you take h as the number of hours she drives, the distance she covers in h hours is 65h. She wants to stop when she is not more than 300 miles from home, which means that she wants to stop when the difference between 850 and 65h is less than or equal to 300.
This expressed as an inequality is:
[tex]850-65h\leq300[/tex]