An exam consists of 10 true-or-false questions. if a student guesses at every answer, what is the probability that he or she will answer exactly 6 questions correctly?

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.