For which of these functions is function composition commutative with ƒ(x) = (x + 1 /3x − 2) ? a - g(x) = (3x − 2/x + 1)b - g(x) = (3x − 3/x + 2)c - g(x) = (2x + 1/3x − 1)d - g(x) = (2x − 1/3x + 1)

The life, in years, of a certain type of electrical switch has an exponential distribution with an average life b = 2. if 100 of these switches are installed in dif- ferent systems, what is the probability that at most 30 fail during the first year?