If the letters in the word poker are rearranged, what is the probability that the word will begin with the letter k and end with the letter p?

The probability is 6/120 or 1/20, which can be expressed as a percentage of 5%.

You can find this by first deciding how many possibilities there are. With a number of items being arranged in a set, the easiest way to solve this is by using the factorial function on your calculator (the button that looks like "!"). It denotes That number by all of the integers lower than it down to 1 multiplied together. 

So since there are 5 letters in poker, we would use 5! or written out:
1*2*3*4*5 = 120. 

Then we would have to find all of the options that start with k and end with p, of which there are exactly 6. 

koerp
korep
kreop
kroep
kerop
keorp

So then we divide the number of possibles by the total number of options.