Question

if y varies inversely as x and y=12 when x=20 then what is y when x is 15

Answer 1

y = k/x (y = 12 and x = 20)
12 = k/20 -- multiply by 20
(20)(12) = k
240 = k

y = 240/x (when x is 15)
y = 240/15
y = 16