Let s be the number of guests who want steak and c be the number who want chicken. We know that s + c = 80 and s = 3c.
Substituting the second equation into the first equation, we get 3c + c = 80
Combining like terms, we get 4c = 80
Dividing both sides by 4, we get c = 20
Then multiply the number of guests who want chicken by the cost of each chicken entree: 20 guests * $18/guest = $<<20*18=360>>360
Then triple the number of guests who want chicken to find the number who want steak: 20 guests * 3 = <<20*3=60>>60 guests
Then multiply the number of guests who want steak by the cost of each steak entree: 60 guests * $25/guest = $<<60*25=1500>>1500
Then add the cost of the steak and chicken entrees to find the total cost: $1500 + $360 = $<<1500+360=1860>>1860
#### 1860