If the electricity bill costs $800, and Cheryl spends $400 more on her monthly cell phone expenses than on the electricity bill, she pays $800+$400 = $<<800+400=1200>>1200 on cell phone expenses.
Since the cost to enter the tournament is 20% more than Cheryl's monthly cell phone expenses, to enter the tournament, Cheryl has to pay 20/100*1200 = $<<20/100*1200=240>>240 more than her monthly cell phone expenses.
The total cost of joining the golf tournament is $1200+$240 = $<<1200+240=1440>>1440
#### 1440