algebra- constant of variation?

Question

c varies jointly as a and b, and c=84 when a=70 and b=30


What is this asking and how do I go about solving?

Answer 1

the phrase "c varies jointly as a and b" means there exists some constant , call it k, such that

c=kab

Plug in your values for c,a,and b, and solve for k.


"c varies jointly with a and inversely with b" would mean

c=ka/b