Question 632554
The original solution is {{{ .4/1= .4 }}}  ( in some units, gallons, etc )
Let {{{ x }}} = the amount of water to be added in same units
You're looking for {{{ .4 / ( 1 + x ) = .01 }}}
{{{ .4 = .01*( 1 + x ) }}}
{{{ .4 = .01 + .01x }}}
{{{ .01x = .4 - .01 }}}
{{{ .01x = .39 }}}
{{{ x = 39 }}}
You had 60% water to begin with
Now you have {{{ ( .6 + x ) / ( 1 + x ) = 39.6 / 40 }}}
{{{ ( 39.6/40)*100 = 99 }}} percent water
( that figures since 1 - .01 = 99 )
{{{ 99 - 60 = 39 }}}
So you increase the percentage of water by 39%