Question 395871

Let {{{x}}} = width of the path
The dimensions of the pool + path are
{{{(20 + 2x)*(10 + 2x) = 600}}}
{{{200 + 60x + 4x^2 = 600}}}
{{{4x^2 + 60x - 400 = 0}}}
{{{x^2 + 15x - 100 = 0}}}
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
{{{a = 1}}}
{{{b = 15}}}
{{{c = -100}}}
{{{x = (-15 +- sqrt( 15^2-4*1*(-100) ))/(2*1) }}} 
{{{x = (-15 +- sqrt( 225 + 400 ))/2 }}}  
{{{x = (-15 + 25)/2 }}} 
{{{x = 5}}}
and
{{{x = (-15 - 25)/2 }}} (can't use a negative result)
The width of the path is 5 m
check answer:
{{{(20 + 2x)*(10 + 2x) = 600}}}
{{{(20 + 10)*(10 + 10) = 600}}} 
{{{30*20 = 600}}}