The forum rules require you show some work
But, do not come back saying you can not remember when attached to the internet
for instance
http://en.wikipedia.org/wiki/Parts-per_notationis a simple search
now once you have looked there, you can come back an say
here is how I calculated ppm
and we will tell you if you are understanding the concept and guide you
by the way === please read forum rules
also you can use subscripts and superscripts here since there are editing features provided in the posting screen