Question 182307
Let {{{h}}}= number of hard drives sold
Let {{{c}}}= number of CD-ROMs sold
Let {{{f}}}= number of floppy drives sold
given:
(1) {{{h + c + f = 300}}}
(2) {{{h = 6c}}}
(3) {{{f = (1/2)*h}}}
--------------------
(1) {{{h + c + f = 300}}}
(2) {{{h = 6c}}}
{{{c = h/6}}}
Substitute in (1):
(1) {{{h + c + f = 300}}}
{{{h + h/6 + h/2 = 300}}}
{{{6h + h + 3h = 1800}}}
{{{10h = 1800}}}
{{{h = 180}}}
and
{{{c = h/6}}}
{{{c = 180/6}}}
{{{c = 30}}}
also
(3) {{{f = (1/2)*h}}}
{{{f = 180/2}}}
{{{f = 90}}}
180 hard drives, 30 CD-ROM drives, and 90 floppy drives were sold