A cell phone plan charges $39.95 a month plus 15 cents per text message sent and 15 cents per message received. Using s to represent the number of text messages sent in one month and r to represent the number of text messages received in one month, the following equation can be used to calculate the total monthly cost, c. C=39.95+.15(s+r)
If it is known that the total monthly cost is $53.45 and 63 text messages were received, solve for s, the total number of text messages sent.