why not do both?

Make ur pre work out and post work out be 15 to 20 mins of jogging which not only helps burn fat , lossening ur mucles but also elavates ur heart rate through an aerobic or cardio mode n prepares u for ur anaerobic workout such as push ups, weights and other muscular strengthening work outs.

yes pre workout is 15 mins n post workout which actually helps prevent muscle aches be about 5 to 10 mins.

in between do ur anaerobic workout out for at least 45 mins, this is the best way to loose weight, build strength n maintain a healthy body.

nope, just three times a week is sufficeint and good enough for u to notice the difference n maintain ur health