Question 33523
{{{ 0.9872^x = 0.5 }}}


Take logs: {{{ log(0.9872^x) = log(0.5) }}}
{{{ xlog(0.9872) = log(0.5) }}}
{{{ x = (log(0.5))/(log(0.9872)) }}}
--> x = 53.80480576
--> x = 53.8048 to 4dp.


Check on your calculator: {{{ 0.9872^(53.8048) }}} is 0.5000000 to 6 dp.


jon.