SOLUTION: Express the statement as a formula that involves the given variables and a constant of proportionality k. r varies directly as s and inversely as t. Determine the value of k fr

Algebra ->  Rational-functions -> SOLUTION: Express the statement as a formula that involves the given variables and a constant of proportionality k. r varies directly as s and inversely as t. Determine the value of k fr      Log On


   

Question 1113887: Express the statement as a formula that involves the given variables and a constant of proportionality k.
r varies directly as s and inversely as t.
Determine the value of k from the given conditions.
If s = −2 and t = 4, then r = 6.
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

if r varies directly as s and inversely as t, we have
r=k%2As%2Ft

If s+=+-2 and t+=+4, then r+=+6, we have:
r=k%2As%2Ft
6=k%2A%28-2%29%2F4
6=k%2A%28-1%2F2%29
k=6%2F%28-1%2F2%29
k=12%2F%28-1%29
k=-12