Multiplication property of inequality -1/2x< -12 simplify it all the way through

Multiply both sides by -2. Doing this will flip the inequality sign. The flip always happens when you multiply both sides by a negative number. 

So we'll go from this
(-1/2)x < -12
to this
x > 24

which is the final answer

Note: If you need to graph x > 24, then plot 24 on the number line. Draw an open circle at 24 and shade to the right of this open circle. The open circle tells the reader "the endpoint 24 is not part of the solution set". 

Edit: the full steps are...

(-1/2)x < -12
-2*(-1/2)x > -2*(-12)
(-2*-1/2)x > 24
2/2x > 24
1x > 24
x > 24

Let me know if that helps or not. Thank you.

The answer is 225 miles per 4.5 hours. hope this ; )