I do not know where to start with this one. Suppose p varies directly as the square of z and inversely as r. If p = 32/5 when z = 4 and r = 10, find p when z = 3 and r = 36.

Answer 1

" p varies directly as the square of z and inversely as r "
----> p = k (√z) (1/r) , where k is a constant

given: p=32/5 , z=4, r=10
32/5 = k(√4)(1/10)
times 10
64 = 2k
k = 32

so p = 32√z/r

then when z=3,r=36
p = 32√3/36
= 8√3/9 or appr 1.54

Answer 2

6x+4(70-x)=300