Final answer:
To find the probability that at least one item will have a defect, subtract the probability of no item having a defect from 1.
Step-by-step explanation:
To find the probability that at least one item will have a defect, we can use the complement rule. The complement of at least one item having a defect is no item having a defect. So, the probability of no item having a defect is equivalent to 1 minus the probability of at least one item having a defect.
The probability of no item having a defect is (1-0.1)^7 = 0.9^7 = 0.4783.
Therefore, the probability that at least one item will have a defect is 1 - 0.4783 = 0.5217.