Question 380330
Let's call the number of texts Mai sent m.  Ryan sent 4*m (4 times as many as Mai).  Mai sent 5 more than Ali, so Ali sent 5 less than Mai: m - 5
Add the number they each sent to get the total: 139
(m) + (4*m) + (m - 5) = 139
6*m - 5 = 139
6*m=144
m = 24
Mai sent 24.  This means Ryan sent 4*24=96 messages, and Ali sent 24-5=19 messages.
Check: 24 + 96 + 19 = 139