The numerator of the probability is the number of ways she can succeed in picking a number greater than 600. There are 4 ways she can pick the first digit as 6,7,8, or 9 That leaves 8 ways she can pick the second digit. That leaves 7 ways she can pick the third digit. So there are 4 ways she can pick a number larger than 600. The denominator of the probability is the number of ways she can pick any number whether smaller or larger than 600. There are 9 way she can pick the first digit. That leaves 8 ways she can pick the second digit. That leaves 7 ways she can pick the third digit. So there are 9 ways she can pick any nunber (whether smaller or larger than 600). So the probability that she will succeed in picking a number greater than 600 is the fraction= = Edwin