Answer:
 Power does it draw from the mains = 2.78 kW
Step-by-step explanation:
 Power = Work / Time.
 Here work done = Energy used by Bat taser = 2.5 MJ = 2.5 x 10⁶ J
 Time taken = 15 minutes = 15 x 60 = 900 seconds.
 Power = Work / Time = 2.5 x 10⁶/900 = 2777.78 Watt = 2.78 kW
 Power does it draw from the mains = 2.78 kW