<p>A CD player chooses a track at random from three discs each with 20 tracks. What is the probability that it chooses track 2 of disc 2?</p>
<p>The answer is 1/60.</p>
<p>The explanation states that the track number is negligible-but what if the three different discs have the same track numbers? then wouldn't it be 1/3 x 1/60? </p>
<p>The discs do have the same track numbers. If the disks were extensions of the previous (disk 1 holds 1 - 20, disk 2 hold 21 - 40, etc.), then it'd be stated.</p>
<p>You could say there's a 1/3 chance of choosing CD 2 and a 1/20 chance of picking track 2 from the 20 tracks on that CD, but you still get 1/3*1/20 = 1/60.</p>