Respuesta :

Formula: an = a1(r)^n-1

n = term number

a1 = first term

r = rate

Plug our values in:

n = 4

a1 = 15

r = 1/3

a4 = 15(1/3)^4-1

a4 = 15(1/3)^3

a4 = 15(1/27)

a4 = 0.5555555556

a4 = 0.6 to the nearest tenth