Question 280080
Let {{{s}}} = sales 3 years ago
After 1st year:
{{{s - .07s = .93s}}}
After 2nd year:
{{{.93s - .07*.93s }}}
{{{.93s - .0651s = .865s}}}
After 3rd year:
{{{.865s - .07*.865s}}}
{{{.865s - .061s}}}
{{{.804s}}}
Cassette sales decreased by 
{{{s - .804s = .196s}}}
(E) 19.6%