A phone company charges $30 per month for a long distance plan plus a charge of $.05 per minute. What would the monthly charge be for someone who talked two and a half hours?

2.5 * 60 = 150 minutes

30 + .05*150

= 30 + 7.5

= $ 37.50

To calculate the monthly charge for someone who talked two and a half hours, we first need to determine the cost per minute. The phone company charges $30 per month for the long distance plan, which is a flat fee. In addition to that, they charge $0.05 per minute for usage.

To calculate the cost per minute, we multiply the charge of $0.05 by the number of minutes in an hour (60 minutes). So, the cost per minute is $0.05 * 60 = $3.

Since the person talked for two and a half hours, we multiply the number of minutes in two and a half hours (150 minutes) by the cost per minute ($3). Therefore, the total talk-time charge is 150 minutes * $3 = $450.

Finally, we add the long distance plan fee of $30 to the talk-time charge of $450. Thus, the monthly charge for someone who talked two and a half hours would be $30 + $450 = $480.