Question 666763
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
y=1000e^-0.056x   || Fins x when y  = 500
{{{500= 1000e^(-.056x)}}}
   {{{ .5 = e^(-.056x)}}}
      ln(.5) = -.056x       || Use Natural logarithm  ln on Your calculator
      ln(.5)/-.056 = x
              12.3776 = x