The amount of money that Sarah earns varies directly with the number of hours worked. If Sarah earns $320 for working 40 hours, determine the constant of proportionality.
(1 point)
A. 9
B. 8
C. 7
D. 6
To solve this problem, we need to set up a proportion using the given information.
Let x be the constant of proportionality. We are told that the amount of money Sarah earns varies directly with the number of hours worked.
So, we can set up the following proportion:
320/40 = x/1
To solve for x, we can cross-multiply:
320 * 1 = 40 * x
Simplifying the equation:
320 = 40x
Divide both sides by 40:
x = 320/40
x = 8
Therefore, the constant of proportionality is 8. The correct answer is B.