Question

A letter lock contains 3 rings, each ring containing 4 letters. All possible trials are made to open the lock and the lock opens in only one way. The probability for the lock to open

• A. $\frac{1}{2}$
• B. $\frac{1}{36}$
• C. $\frac{1}{64}$
• D. $\frac{1}{16}$

Answer 1

The correct option is C $\frac{1}{64}$

Total $=4\ast 4\ast 4=64$
Probability$=1/64$