Select the correct answer.

Sharon makes headbands and sells them online. She is analyzing the sales of two of her most popular styles. For style A, she sold 40 in the first month and had a [tex]$10 \%$[/tex] increase in sales each month after that. For style B, she sold 20 in the first month and had a [tex]$15 \%$[/tex] increase in sales each month after that.

Which system of equations can she use to determine the number of months, [tex][tex]$m$[/tex][/tex], until the sales, [tex]$s$[/tex], are the same for both headband styles?

A. [tex]s=10(40)^m[/tex]
[tex]s=15(20)^m[/tex]

B. [tex]s=1.1(40)^m[/tex]
[tex]s=1.15(20)^m[/tex]

C. [tex]s=40(1.1)^m[/tex]
[tex]s=20(1.15)^m[/tex]

D. [tex]s=40(0.10)^m[/tex]
[tex]s=20(0.15)^m[/tex]



Answer :

To determine the number of months needed until the sales are the same for both headband styles, Sharon needs to create a system of equations that model the sales growth for each style.

Let's examine each style:

1. Style A:
- The initial sales for Style A is 40 headbands.
- The sales increase by [tex]\(10\%\)[/tex] each month. This can be represented by multiplying the sales by [tex]\(1.1\)[/tex] each month.
- Therefore, the sales after [tex]\(m\)[/tex] months can be written as [tex]\(s = 40 \times (1.1)^m\)[/tex].

2. Style B:
- The initial sales for Style B is 20 headbands.
- The sales increase by [tex]\(15\%\)[/tex] each month. This can be represented by multiplying the sales by [tex]\(1.15\)[/tex] each month.
- Therefore, the sales after [tex]\(m\)[/tex] months can be written as [tex]\(s = 20 \times (1.15)^m\)[/tex].

Given these equations, the system of equations that represent the sales growth of both styles is:
[tex]\[ s = 40 \times (1.1)^m \][/tex]
[tex]\[ s = 20 \times (1.15)^m \][/tex]

Upon examining the options, option C correctly represents the system of equations:
[tex]\[ s = 40 \times (1.1)^m \][/tex]
[tex]\[ s = 20 \times (1.15)^m \][/tex]

Thus, the correct answer is:
C. [tex]\(s = 40(1.1)^m\)[/tex]
[tex]\[ s = 20(1.15)^m \][/tex]

This system of equations can be used to determine the number of months, [tex]\(m\)[/tex], until the sales are equal for both headband styles.