High School

We appreciate your visit to The average annual cost in dollars to attend a local college after 1985 can be modeled by the function tex D x 3125 1 65. This page offers clear insights and highlights the essential aspects of the topic. Our goal is to provide a helpful and engaging learning experience. Explore the content and find the answers you need!

The average annual cost, in dollars, to attend a local college after 1985 can be modeled by the function [tex]D(x) = 3125(1.65)^{\frac{x}{9}}[/tex], where [tex]x[/tex] is time measured in years after 1985.

Which of the following expressions reveals the monthly growth factor?

A. [tex]3125(0.088)^{12x}[/tex]
B. [tex]3125(1.005)^{12x}[/tex]
C. [tex]3125(1.057)^{12x}[/tex]
D. [tex]3125(1.138)^{12x}[/tex]

Answer :

To find the monthly growth factor from the given function [tex]\( D(x) = 3125(1.65)^{\frac{x}{9}} \)[/tex], we'll follow these steps:

1. Understand the Current Function:
- The function models the average annual cost as an exponential function, where the base [tex]\( 1.65 \)[/tex] is the annual growth factor over a period of 9 years.

2. Relate Annual and Monthly Growth Factors:
- If we know the annual growth factor, we can find the monthly growth factor by taking the 12th root of the annual growth factor because there are 12 months in a year.

3. Calculate the Monthly Growth Factor:
- Given that the annual growth factor [tex]\( a \)[/tex] is [tex]\( 1.65 \)[/tex], the monthly growth factor [tex]\( m \)[/tex] can be calculated using the relation [tex]\( m^{12} = a \)[/tex], which gives us:
[tex]\[
m = a^{\frac{1}{12}} = 1.65^{\frac{1}{12}}
\][/tex]

4. Result:
- The calculated monthly growth factor is approximately [tex]\( 1.0426 \)[/tex].

5. Match with Given Options:
- We must convert this monthly growth factor to an expression that scales monthly growth over a period, represented as [tex]\( (monthly \, factor)^{12x} \)[/tex].
- Out of the given options, [tex]\( 3125(1.057)^{12x} \)[/tex] closely matches our calculated monthly growth factor.

Thus, the correct expression revealing the monthly growth factor is:
[tex]\[ 3125(1.057)^{12x} \][/tex]

Thanks for taking the time to read The average annual cost in dollars to attend a local college after 1985 can be modeled by the function tex D x 3125 1 65. We hope the insights shared have been valuable and enhanced your understanding of the topic. Don�t hesitate to browse our website for more informative and engaging content!

Rewritten by : Barada