What is the probability that a 7-digit phone number contains at least one 8? (Repetition of numbers and lead zero are allowed).

Let's compute the probability that a 7-digit phone number does not contain 8s, at all.

This means that, for each of the 7 digits, we have 9 choices (the ten digits except 8).

So, there are 7-digit phone numbers that don't contain 8s.

Note that the total number of 7-digit phone numbers is , because we have 10 choices (the ten digits) for each of the seven slots.

So, the probability of finding a phone number with no 8s is

This implies that the probability that a 7-digit phone number contains at least one 8 is the complementary probability

answer: given that the roller coaster can accommodate 1600 riders per hour, thus the roller coaster can accomodate 1600 / 60 = 26.67 riders per minute.

given that there are 345 people in the line, the number of minutes it will take for the 345 persons to get into the roller coaster is given by 345 / 26.67 = 12.94 minutes.

therefore, it will take you 12.94 minutes to get to the front of the line.

step-by-step explanation:

e) none of the above because the measure of angle cba is 101°