Write an Equation to Describe the Variation $\mathrm { s }$

Multiple Choice

Write an equation to describe the variation. Use k for the constant of proportionality.
- $\mathrm { s }$ varies directly as $\mathrm { t }$ and inversely as the square of $\mathrm { u }$ .

A) $\mathrm { s } = \frac { \mathrm { ku } ^ { 2 } } { \mathrm { t } }$
B) $s = \frac { k t } { u ^ { 2 } }$
C) $\operatorname { stu } ^ { 2 } = \mathrm { k }$
D) $\mathrm { s } + \mathrm { t } - \mathrm { u } ^ { 2 } = \mathrm { k }$