To solve this problem, let's assign variables to the number of messages each person sent.
Let's say Chris sent x messages.
According to the problem, Salma sent 9 more messages than Chris, so Salma sent x + 9 messages.
Felipe sent 4 times as many messages as Chris, so Felipe sent 4x messages.
The total number of messages they sent is 111, so we can write an equation to represent this:
x + (x + 9) + 4x = 111
Combining like terms, we get:
6x + 9 = 111
Subtracting 9 from both sides, we get:
6x = 102
Dividing both sides by 6, we get:
x = 17
So, Chris sent 17 messages, Salma sent 17 + 9 = 26 messages, and Felipe sent 4 * 17 = 68 messages.