The value p varies directly with q^-1. If p=1/6 when q=5/8, what is the value of p when q=18?

Question

A)864/5
B)7/24
C)5/864
D)-8/135

I did the p=kq, and found p to be 24/5 but that's not a choice. Help!!

Answer 1

p varies directly with q^-1
not
p varies directly with q^

p = k/q
so, pq = k, a constant. You want p such that

18p = (1/6)(5/8)
18p = 5/48
p = 5/864