Question

A three digit number is formed by using numbers 1, 2,3 and 4. The probability that the number is divisible by 3, is

• A. $\frac { 3 } { 4 }$
• B. $\frac { 1 } { 2 }$
• C. $\frac { 2 } { 7 }$
• D. $\frac { 2 } { 3 }$

Answer 1

Answer: (B)

$\frac { 1 } { 2 }$

Answer 2

Total no. = ⁴P₃ = $\lfloor 4$ = 24

No. divisible by 3 is 2, 3, 4 is used or 1, 2, 3 is used

= $\lfloor 3 + \lfloor 3$ = 12 | P = $\frac { 12 } { 24 } = \frac { 1 } { 2 }$