Is it supposed to be 4< 5•n=11? (i used n as a variable)

If jobs arrive every 15 seconds on average, what is the probability of waiting more than 30 seconds?

Tom says that he needs 6 rolls to obtain each possible outcome on a 6-sided die. on the fourth roll, he rolls his second "3”. tom says that the die is loaded and that each outcome is not equally likely. is tom correct here? if you think tom is incorrect, how many rolls should tom make until he sees each number occurring about 1/6 of the time?

Find the median of the set of data this box-and-whisker plot represents. 15 16 17 18