Your answer to 1) is correct but is 0.327%
For 2) find the chance that 6 machines will fail, and the chance 5 will fail, same for 4, 3, 2, 1, 0 machines and add up all the chances. That is the chance that 6 or less will fail. Remember that [chance 6 or less fail] + [chance more than 6 will fail] = 1
Use this fact to find the chance that more than 6 will fail.
Discuss your findings they probably just want you to talk about [chance 6 or less fail] + [chance more than 6 will fail] = 1 and how it is faster and still valid.