Asnail finds itself at the bottom of a well. the well is 1530 centimeters deep. each day the snail struggles up 180 centimeters and then stops to rest. while it is resting the snail slides down 30 centimeters. how long before it reaches the top of the well?

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.