A letter lock consists of three rings each marked with six different letters. The number of distinct unsuccessful attempts to open the lock is at the most ?
A. 215
B. 254
C. 216
D. 268
Answer:A
A letter lock consists of three rings each marked with six different letters. The number of distinct unsuccessful attempts to open the lock is at the most ?
A. 215 B. 254 C. 216 D. 268