why this is marked incorrectly Je suis arrivé dans cinq minutes." I'll be there in five minutes while this is given in lesson Je suis là dans de

Je suis arrivé -- I arrived. This is past tense, not future tense.

I'll be there in 5 minutes. -- J'arrive dans 5 minutes.

In French you use present tense in this case because it is the immediate future.

Salut Abdul,

Further to Chris's answer:-

When you write "Je suis arrivé ...."   This means, having used the passé composé; that you are expressing a completed "state" of being "arrived" but then the text doesn't make sense when followed by "dans  ...."  which indicates a future situation, ie. something yet to happen.

Je suis là dans deux minutes --  this is consistent with the lesson   "I am there in two minutes"

Using the present tense to indicate an immediate future situation.

Bonne continuation

Jim