Express the statement as a formula.M varies directly as x and inversely as y
Use the information that if x = -20 and y = 4 then M = -25 to find the constant of proportionality.
A) 15
B) 7
C) 5
D) 6
E) 9

Question

Express the statement as a formula.M varies directly as x and inversely as y
Use the information that if x = -20 and y = 4 then M = -25 to find the constant of proportionality. 
A) 15
B) 7
C) 5
D) 6
E) 9

Quizplus · Accepted Answer

The formula for direct and inverse variation is $M = k\frac{x}{y}$, where $k$ is the constant of proportionality. Substituting the given values, $-25 = k\frac{-20}{4}$. Solving for $k$, we find $k = 5$.

Express the Statement as a Formula