Which property is being used?

2-digit numbers less than 91 which are 1 less than a multiple of 10

Me i'm timed right now! a. (0,-5)b. (0,-3)c. (0,3) d. (0,5)

A. the probability that a product is defective is 0.1. what is the probability that there will be 1 or less defective products out of the next 8 produced products b.the expected number of imperfections in the coating nylon for parachutes is 6 per 100 yards. what is the probability of finding 12 or fewer imperfections in 260 yards c.in a lot of 54 products there are 9 defective products. calculate the probability that not more than 1 is defective from a random sample of 17 products.