High School

After the journalism club sold 60 magazines, it had [tex]$220[/tex] in profit. After it sold a total of 100 magazines, it had a total of [tex]$420[/tex] in profit.

Which equation models the total profit, [tex]y[/tex], based on the number of magazines sold, [tex]x[/tex]?

A. [tex]y + 220 = 2(x + 60)[/tex]

B. [tex]y - 220 = 5(x - 60)[/tex]

C. [tex]y - 220 = 2(x - 60)[/tex]

D. [tex]y + 220 = 5(x + 60)[/tex]

Answer :

To find the correct equation that models the total profit, [tex]\( y \)[/tex], based on the number of magazines sold, [tex]\( x \)[/tex], we can use the given points: (60 magazines, [tex]$220 profit) and (100 magazines, $[/tex]420 profit).

1. Determine the slope (m) of the line:

The slope formula is:
[tex]\[
m = \frac{y_2 - y_1}{x_2 - x_1}
\][/tex]

Substituting the values from the points (60, 220) and (100, 420):
[tex]\[
m = \frac{420 - 220}{100 - 60} = \frac{200}{40} = 5
\][/tex]

So, the slope, [tex]\( m \)[/tex], is 5.

2. Use the point-slope form to write the equation:

The point-slope form of a line is:
[tex]\[
y - y_1 = m(x - x_1)
\][/tex]

Using the point (60, 220) and the slope [tex]\( m = 5 \)[/tex]:
[tex]\[
y - 220 = 5(x - 60)
\][/tex]

This is the equation that models the relationship between the profit, [tex]\( y \)[/tex], and the number of magazines sold, [tex]\( x \)[/tex].

The correct choice from the options provided is:
B. [tex]\( y-220=5(x-60) \)[/tex].

Other Questions