There are 5 locks and 5 keys and each of the 5 keys matches each of the 5 locks. What is the minimum and the maximum trial numbers of attempts R needed to confirm that each of the 5 keys matches each of the 5 locks? Choose the correct option.
A) 5,15
B) 4,15
C) 5,10
D) 4,10
E) 5,20
Assume you have locks 1-5 and keys A-E.   Minimum: assume you are lucky to find the correct key/combo on the first try. So, 1 -&gt; A, 2 -&gt; B, 3 -&gt;C, and 4 -&gt; D, then 5 must match with E. Therefore, you only need to try 4 combos at a minimum.   Maximum: assume that it takes as many guesses as possible. So, with the first key you try A, B, C, and D with no success, therefore E must be the match (so 4 attempts). For key 2 you no longer have E available so you try A, B, and C, with no success, therefore D must be the match (3 attempts). And so on for key 3 (2 attempts) and key 4 (1 attempt). Key 5 matches with the remaining lock for a total of R=4 + 3 + 2 + 1= 
<gadget id="calculator">4 + 3 + 2 + 1</gadget>
<output>10</output>
10 attempts.4,10
<result>D</result>
There are 5 locks and 5 keys and each of the 5 keys matches each of the 5 locks. What is the minimum and the maximum trial numbers of attempts R needed to confirm that each of the 5 keys matches each of the 5 locks?