Answer:
Step-by-step explanation:
Let g represent the number of messages Goran sent. Then 4g is the number Rafael sent, and g+8 is the number Lucy sent. Their total is ...
 (g+8) +g +4g = 140
 6g = 132
 g = 22
 g+8 = 30
 4g = 88
Lucy sent 30 messages; Goran sent 22; and Rafael sent 88.