Suppose that z varies jointly as u and v and inversely as w, and that z=.8 and when u=8, v=6, w=5. How do you find z when u=3, v=10 and w=5?

1 Answer
Sep 26, 2017

z=4/5

Explanation:

"the initial statement is "zprop(uv)/w

"to convert to an equation multiply by k the constant"
"of variation"

rArrz=(kuv)/w

"to find k use the given condition"

z=0.8" when "u=8,v=6,w=5

z=(kuv)/w

rArrk=(wz)/(uv)=(5xx0.8)/(3xx10)=0.8/6=8/60=2/15

"equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(z=(2uv)/(15w))color(white)(2/2)|)))

"when "u=3,v=10" and "w=5

rArrz=(2xx3xx10)/(15xx5)=60/75=4/5