## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$y=0.1\cdot xz$
If $y$ varies jointly as $x$ and $z,$ then $y=kxz.$ Given $x=5, z=4, y=2$, we find k $2=k\cdot 5\cdot 4$ $2=20k\qquad$... divide with $20$ $k=\displaystyle \frac{2}{20}=0.1$ $y=0.1\cdot xz$