Answer:
to find the max number of guests:
25x-400 = 50
25x = 50 + 400
25x + 450
then divide
x = 450/25
x = 18
to find the min number of guests:
25x = 400 - 50
25x = 350
then divide
x = 350/25
x = 14
Minimum number of tables reserved:
is dividing the max/7 per table
x = 18/7
x = 3
Explanation: