Question 951889
The break-even point is where
cost, {{{ c }}} = revenue {{{ r }}}
Let {{{ n }}} = number sold
{{{ c = 1250 + 40n }}}
{{{ r = 60n }}}
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{{{ c = r }}}
{{{ 1250 + 40n = 60n }}}
{{{ 20n = 1250 }}}
{{{ n = 62.25 }}}
You can't sell 1/4 of of air filter, so
you need to sell {{{ 63 }}} to
break even
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Here's plots of {{{ c(x) }}} and {{{ r(x) }}}:
{{{ graph( 400, 400, -10, 80, -500, 5000, 40x + 1250, 60x ) }}}