Hello you answered my previous Question and thank you a lot. But i need one more clarification that i dont understand well. If i buy the Tickets Mobilis 1-4 zone will it be good to travel until Chelles which served by Chelles – Gournay station on Paris RER line 
and on the Transilien Paris – Est suburban rail line 
. As it writen that it covers only metro lines. Does it cover RER Lines? and Transilien lines? If not then it should be better to take the Navigo Day Pass that covers all ? Correct ? Thanks in Advance for the Answer.
1 answer
Chelles - Gournay station is within Paris fare zone 4 as shown on Paris public transportation zone maps and Ticket Mobilis is valid for both RER & Transilien (in addition to Metro & Buses) so you can use either RER E line or Transilien P lines.
Don't hesitate to post other questions should anything else be unclear.