probability theory question: mean subsequent block time

I'm trying to arrive at the function that describes the following, but can't quite figure it out for multiple blocks. (there are some useful insights for a single block here.)

assume the Poisson point process that is the arrival of proof-of-work blocks on Monero. the mean of the block times is the target block time t (120 seconds).

also assume n subsequent blocks.

also assume p, the probability of n subsequent blocks having a mean block time less than or equal to T.

given t, n and p, how can I calculate T?