Final answer:
Mr. Smith sent 15 messages each day.
Step-by-step explanation:
To find out how many messages Mr. Smith sent each day, we can divide the total number of messages he sent by the number of days in the week, including the weekend.
Mr. Smith sent a total of 105 messages in a week. Since there are 7 days in a week, including the weekend, we can divide 105 by 7 to find out how many messages he sent each day.
105 ÷ 7 = 15
Therefore, Mr. Smith sent 15 messages each day.