An option that sorts the three friends in order from least to greatest dollar amount saved per week is: C. Scarlett, Nolan, Zahra.
In Mathematics and Geometry, the slope-intercept form of the equation of a straight line is given by this mathematical equation;
y = mx + c
Where:
- m represents the slope or rate of change.
- x and y are the points.
- c represents the y-intercept or initial value.
Note: There are 7 days in a week.
Since Nolan started with $40 and added $12.50 every week, a linear equation that models the situation is given by;
y = mx + c
y = 12.50x + 40
When x is 7, the total savings is given by;
y = 12.50(7) + 40
y = $127.50
For Zahra, her total savings can be modeled as follows;
Slope (m) = (193 - 113)/(9 - 5)
Slope (m) = 20
By using the point-slope form, a linear equation that models the situation is given by;
y - 113 = 20(x - 5)
y = 20x + 13
When x is 7, the total savings is given by;
y = 20(7) + 13
y = $153.00
For Scarlett, his total savings can be modeled as follows;
Slope (m) = (125 - 90)/(6 - 4)
Slope (m) = 17.5
By using the point-slope form, a linear equation that models the situation is given by;
y - 90 = 17.5(x - 4)
y = 17.5x + 20
When x is 7, the total savings is given by;
y = 17.50(7) + 20
y = $142.50