For this case we have that by definition, the average power is given by:
[tex]P = \frac {W} {t}[/tex]
Where:
W: It is the work done
t: It's time
According to the data we have to:
[tex]W = 250 \ KJ = 250,000 \ J\\t = 45 \ s[/tex]
So:
[tex]P = \frac {250,000} {45}\\P = 5555.55 \ watts = 5.56 \ kw[/tex]
Answer:
[tex]5.56 \ kw[/tex]