Acatering company uses different functions to estimate the itemized costs for a party. the table below represents the included tip for wait staff as a function of the number of guests served. if the tip varies directly with the number of guests, which equation represents the relationship between the tip, t, and the number of guests, g?

#of guests   waitstaff tip
10                      18
20                      36
30                      54
40                      72
50                      90

If the tip varies directly with the number of guests, which equation represents the relationship between the tip, t, and the number of guests, g? 
t = 1.8g t = g/18 g = 1.8t g = t/18

18/10 = 1.8
36/20 = 1.8
54/30 = 1.8

direct variation: t = 1.8g

Idon't know the answer