Question

Pavement requires aggregate of specific size. Aggregates for a highway pavement are extracted from a gravel pit. Based on experience with this area, it is known that the probability of good-quality aggregate is only 80%. In order to weed out poor-quality aggregate, engineers on site use a quick test, which is not entirely reliable. The probability that a good-quality aggregate passes is 90%, whereas the probability that a poor-quality aggregate will pass is 20%.

1. What is the probability that a random sample of gravel from the pit passes the test?
2. What is the probability that a passing sample is poor-quality?
3. What is the overall accuracy of this test?

Answer 1