in 1985, there were 285 cell phone subscribers in the small town of Centerville. the number of subscribers increased by 75% per year after 1985. how many cell phone subscribers were in Centerville in 1994.

  43,872

Step-by-step explanation:

The growth of cell phone subscribers in Centerville can be modeled by an exponential function.

  y = ab^x . . . . . where a = initial value, b = growth factor

The growth rate is given as 75% per year, so x will have units of years. It will be zero for the year 1985. The growth factor is ...

  b = 1 + growth rate = 1 +0.75 = 1.75

Then the model is ...

  y = 285·1.75^x

__

For x = 1994 -1985 = 9, the number of subscribers is modeled as ...

  y = 285·1.75^9 ≈ 43,872

The model predicts 43,872 cell phone subscribers in 1994.

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

~