Question

D varies as r and s, inversely as t. If D=12, r=3, s=20, and t=5, find D when r=15, s=4, and t=8.

Answer 1

Answer:

D varies r and s, inversely as t

so, D= k.r.s/t where k is constant

if , D=12,r=3,s=20,t=5

then, 12=k.3.20/5

=> 12=12k

=> k=12/12=1

when r=15, s=4 , t=8 then

D=1.15.4/8=15/2=7.5