Initial subscribers: 285
Increase rate : 75 % = 75/100 = 0.75 (decimal form)
years passed = 1994-1985 = 9 years
Apply the formula:
A = P (1 +r ) ^ t
Where:
A = number of cell phone subscribers after t years
P = initial suscribers
r= increase rate in decimal form
t= years
Replacing:
A = 285 (1 +0.75)^9 = 43,872