Answer:
a) 100 + 15x
b) $400
Step-by-step explanation:
To find out the equation for the first part, we know that the cost of the banquet room for an event is $100. To add, for each guest (x), we add another $15, which means you have to multiply the price of each guest with the number of guests (x)
To find out part (b), you have to substitute x as 20 in the equation and you shall arrive at the answer of $400