Question 278339
n varies directly as q.
n = 39 when q = 3
find n when q = 8


n varies directly as q means that n = k*q


this means that:


39 = k*3


divide both sides of this equation by 3 to get:


k = 13


now that you have the value of k, you can solve for finding n when q = 8


you get:


n = k*q becomes n = 13*8 which becomes n = 104


in a direct variation problem, the ratio between n and q remains the same.


this means that n1 is to q1 as n2 is to q2.


in formula terms, this would be n1/q1 = n2/q2


in your problem, this becomes:


39/3 = 104/8


cross multiply and you get 39*8 = 3*104 which becomes 312 = 312 confirming that the ratio is the same between the 2 numbers of n/q.