Answer:
You have three card : 3, 4, 5 and 6.
You first pick one card randomly, the probability of picking a 3 is:
P = 1/4
You then pick a second card without putting the first card back, the probability of picking a 3 is:
P = 1/3
=> The probability of picking a 3 and then picking a 3:
P = (1/4) x (1/3) = 1/12
Hope this helps!
:)