If z varies inversely as w, and z=10 when w=0.7, how do you find z when w=20?

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Answer 1 · 2016-06-25T13:24:20

When $w= 20, z = 0.35$

As per data provided :
$z=10 ,$ when $w =0.7$

As $z$ is inversely proportional to $w:$

$color(blue)(z prop 1/w$

Introducing constant $k:$

$z = k xx 1/w$

$z = k/w$

$k = z xx w$

$k = 10 xx 0.7$

$color(blue)( k = 7$

Now, we are required to find $z$ , when $w = 20.$

$z = k/w$

Substituting values for $k$ and $w:$

$z = 7/20$

$z = 0.35$