Step 1:
Write the given data
Cost of renting hall = 300
Charge per guest = 65
Step 2:
Write an equation to represent the cost function
y = Total cost
x = number of guest
y = 300 + 65x
Step 3:
y = 300 + 65x
x = 75
Substitute x in the equation to find the total charge for 78 attendees.
[tex]\begin{gathered} y\text{ = 300 + 65 }\times\text{ 78} \\ y\text{ = 300 + 5070} \\ y\text{ = 5370} \end{gathered}[/tex]Final answer
The total charge of 78 attendees = 5370
