# Question #d27b1

Nov 29, 2016

Z varies directly as x and inversely as y.

So $z \propto \frac{x}{y} \implies z = k \frac{x}{y}$,where k is variation constant.

Now $z = 123 w h e n x = 6 \mathmr{and} y = 6$

So $123 = k \times \frac{6}{6} \implies k = 123$

So when $x = 7 \mathmr{and} y = 8$ then z becomes
$z = 123 \times \frac{7}{8} = \frac{861}{8}$