Question 378932
Let x be the number of chairs/row and r be the number of rows.
You are told
{{{x*r = 48}}}
and
{{{x = 2r - 10}}}
So
{{{x*r = 48}}}
{{{(2r - 10) * r = 48}}}
{{{2r^2 - 10r = 48}}}
{{{2r^2 -10r - 48 = 0}}}
{{{r^2 - 5r - 24 = 0}}}
{{{(r - 8)(r + 3) = 0}}}
So r can be either 8 or -3. Since the number of rows can't be negative,
there must be 8 rows.
If there are 8 rows, then {{{x*8 = 48}}} 
thus {{{x = 6}}}

8 rows of 6 chairs each