6 (a) A box contains 9 tickets numbered from 1 to 9 inclusive. If 3 different tickets are drawn from the box one at a time, find the probability that they are alternatively either odd, even, odd or even, odd, even. (b) A manufacturer purchases two machines A and B. The probability that A will last five years is _ and the probability that B will last five years is 2. Find the probability that (i) both machines will last five years; only machine A will last five years; (iii) at least one machine will last five years; (iv) neither machine will last five years. 7 (a) A pair of fair dice is tossed once, what is the probability of scoring a total of 7 points? (b) In two tosses of a pair of fair dice, find the probability of scoring a total of 7 points (i) once; (ii) at least once; (iii) twice