The tickets in a box are numbered from 1-20 inclusive. if a ticket is chosen at random and replaced, and then a second ticket is drawn at random, what is the probability that the sum of their numbers is even?

Afactory buys 10% of its components from suppliers b and the rest from supplier c. it is known that 6% of the components it buys are faulty. of the components brought from suppliers a,9% are faulty and of the components bought from suppliers b, 3% are faulty. find the percentage of components bought from supplier c that are faulty.