the right time at which the plane supposed to arrive at its destination = 8:00 pm
but arrived at =8:16 pm
time extra taken = 16 minutes
there are four 15 minutes in an hour  and 32 15 minutes in 8 hours
seconds  the plane was late = 16 x 60
                       = 960
seconds the plane was late in every fifteen seconds = 960 /32
                                          = 30
(ans) = 30 seconds