The electric company charges Tk. 30 per kilowatt-hour (KWH), Rahim used 2800 KWH in April, 3200 KWH in May, and 3600 KWH in June. What was his average cost of electricity for the 3 months?

A Tk. 72

B Tk. 96

C Tk. 48

D Tk. 144

Correct Answer: Option E

total used= 2800+3200+3600=9600 kwh total cost= 0.30 X 9600=2880 tk average= 2880/3=960 tk