The probability of more than 7 customers arriving within a minute is obtained by taking the probability at X equal to 0, 1, 2, 3, 4, 5, 6, and 7 then subtracting from the total probability. It can be expected about 1.2% of times that more than 7 customers arriving within a minute.
Rise over run. as time increases the temperature rises. starting at 8am and -2°f. At 12pm the temperature rose to 4°f. that's a difference of 4 hours and 6 degrees. for every hour, it rose 1.5 degrees. the slope is 1.5/1