# Toy probability

**Discrete Mathematics**Level 3

A bin contains 25 toys, 5 of which are of good quality ,i.e., they can work infinite times , 10 of the remaining are partially good ,i.e., they will fail to work the 2nd time. Remaining 10 toys are of bad quality which will not work even at the first attempt. A toy is selected at random. What is the probability that the selected toy to continue to work when it is given that the first time it worked perfectly ?