You can
put this solution on YOUR website!Probability is (total number of desired outcomes)/(total number of possibly outcomes)
Desired outcome: you want 1 king, and 4 other cards
To get that, you use combinatorics:
4C1 x 48C4 = 778320
Total outcome: 5 card hand
To get that, you do 52C5 = 2598960
Then the probability is
P(1 king in a 5 card hand)= 778320 / 2598960 = 0.299