What is the cost to operate this appliance for 25 minute(s), if the cost of electricity is $ 0.12/kWh

The voltage and current to an electrical appliance are as follows: V(t) = 55 sin (420 t) volts and I(t) = 82 sin (420 t) amperes, where the time variable t has the units of seconds.
What is the cost to operate this appliance for 25 minute(s), if the cost of electricity is $ 0.12/kWh?

i tried 0.11275 and failed, help me


some info that may be useful:
sin & cos are in radians
f = 66.845076098596 Hz
Vrms = 38.8908729652601 V
T = 14.9599650170943 ms
Pavg = 2255 W
& i think working may involve root mean squares

thank you!

V peak = 55 volts
I peak = 82 amps
V rms = 55/√2 = 38.89 volts
I rms = 82/ √2 = 57.98 amps
Power = Vrms* I rms =( 55/√2)(82/√2) = (1/2)55(82) = 2,255 watts
If it runs for 25 minutes, it will use 2,255(25/60) =932.58 watt hours = 0.9326 Kwh
It will cost 0.12*0.9326 = 0.113 dollars or 11.3 cents to run this appliance for 25 minutes