Question 1204487
<pre>
                  PRICE       QTY.       COST

HARDCOV             h          5         5h

PAPERB             h-2         4       4(h-2)

Total                                    100
</pre>
If this table of data is understood then you know what to do.


Think carefully about the COST column and you could see  {{{9h-8=100}}}
and then {{{9h=108}}} showing an obvious multiple of 9.
{{{h=12}}}.