A letter lock consists of three rings each marked with four different letters. The number of distinct unsuccessful attempts to open the lock is at the most?  Choose the correct choice from the following answers
A) 63 B) 64 C) 65 D) 67 E) 90
Since each ring consists of four different letters, the total number of attempts possible with the three rings is   = 4* 4 * 4= 
<gadget id="calculator">4* 4 * 4</gadget>
<output>64</output>
64. Of these attempts, one of them is a successful attempt.   Maximum number of unsuccessful attempts= 64 - 1= 
<gadget id="calculator">64 - 1</gadget>
<output>63</output>
63.   63nswer: 63
<result>A</result>
A letter lock consists of three rings each marked with four different letters. The number of distinct unsuccessful attempts to open the lock is at the most?