Answer:
3 (g + 0.07g)
Explanations:
Cost of 1 pack of gum = g
Cost of 3 packs of gum = 3g
7% of sales tax = (7/100) x 3g = 0.07 x 3g = 0.07(3g)
The cost of 3 packs of gum and 7% sales tax = 3g + 0.07(3g)
The cost of 3 packs of gum and 7% sales tax = 3 (g + 0.07g)