Assuming Metropolis is about where New York City is in our universe;
New York to Hong Kong about 7,000 miles speed of sound aprox 770 mph Nine (9) Hours for her scream to be heard by Superman
If some special telepathic link kicks in and he takes a quick trip
Escape velocity ~6.96 mi/s (If he goes any faster he will fly into space)
I.E. 27 seconds or so for Clark to reach Metropolis
