3-digit numbers are formed using the digits 1,3,7 without repetition of digits. A number is randomly selected. What is the probability that the number is divisible by 3 ?

Step-by-step solution

Total 3 digits numbers formed by 1,3,7 without repetition =3 2 1=6 Sum of digits =1+3+7=11 A number is divisible by 3 when the sum of digits of the number is either divisible by 3 or a multiple of 3 but 11 is neither the multiple of 3 nor divisible by 3 . aligned & n( E )=0 & n( ~S )=6 & Probability = n( E ) n(S) = 0 6 =0 aligned