Question 1184831
the total cost is 500 a month plus 2.5 for each message over 100.


if the utilization is less than or equal to 100 messages a month, then the total cost is 500.


if the utilization is more than 100 message a month, then the total cost is 500 plus (number of messages that month minus 100).


if the user consumed 250 message a month, the total charge would be 500 plus 2.5 * (250 - 100) = 500 plus 2.5 * 150 = 875.


for any number of message under or equal to 100, the total cost is 500.


after that, the total cost is 500 plus 2.5 * any number of messages greater than 100.