At time 0, a gentleman buys three automobiles. The automobiles are indistinguishable to the naked eye. However, their lifetimes are random variables with different distributions. One of them has a lifetime which is exponentially distributed with a mean of 5, another has a lifetime which is exponentially distributed with a mean of 6. Calculate the probability that the second failure of one of the gentlemen's automobiles (not the second failure of a single car) occurs before time point 10.