Question

In 1985, there were 285 cell phone subscribers in the small town of Glenwood. The number of subscribers increased by 75% per year after 1985. How many cell phone subscribers were in Glenwood in 1990?

Answer 1

In 1990, there are about 4,677 phone subscribers.
For every year, you multiply the number of subscribers by 1.75, to show the increase in subscribers.

Answer 2

4676.85 cell phone subscribers were in Glenwood in 1990 .

Explanation:

As the exponential increase function is denoted by.

`y = a (1 + r)^(t)`

Where a is the initial value , r is the rate of interest in the decimal form and t is time.

As given

In 1985, there were 285 cell phone subscribers in the small town of Glenwood.

The number of subscribers increased by 75% per year after 1985.

75% is written in the decimal form

`= (75)/(100)`

= 0.75

a = 285

r = 0.75

As the year changes from 1985 to 1990 .

t = 1990 - 1985

t = 5

Put in the expontential increase function.

`y = 285 (1 + 0.75)^(5)`

`y = 285 (1.75)^(5)`

y = 285 × 16.41

y = 4676.85

Therefore 4676.85 cell phone subscribers were in Glenwood in 1990 .