The long distance company that you use charges $5.00 per month and $0.10 per minute per call. if your current bill is $25.00, how many minutes did you use?

Assuming that this is for one month and the carrier just takes the ceiling of the total number of minutes that were spent making phone calls in total, you would have 25-5-(.1x)=0. This reduces to 20/.1=x where x = 200. Is that all the info they gave?

The expressions would be 0.25a