Why is there no need in "ke" before aaje and piche?
Because the English does not include the word of (के).
It doesn't mean I am ahead of you and you are behind of me.
I wonder about the different versions of you... aap,, tum and tu... they seem to be used interchangeably and that is not maybe true...
मैं आगे हूँ और आप पीछे हैं।
मैं आगे हूँ और तुम पीछे हो।
मैं आगे हूँ और तू पीछे है।
Please refer to the last section of this page to understand this concept! :D
Aap is a formal version of you. It is used for people of respect.
Tum is neutral but it is 75% informal and 25% informal.
Tu is a informal word.