Question

The number of 5 digited numbers that can be formed using the digits 0,1,2,3,4,5 that are divisible by 6 when repetition is not allowed is

Answer 1

a) _ _ _ _ _ $\underset{–}{0}$

b) _ _ _ _ _ $\underset{–}{2}$

c) _ _ _ _ _ $\underset{–}{4}$

Only these numbers will be divisible when repetition is not allowed and ${}^{\prime }{0}^{\prime }$ cannot be the first digit.

$a)5\times 4\times 3\times 2=120$

$\begin{array}{c}b)4\times 4\times 3\times 2=96\\ c)4\times 4\times 3\times 2=96\end{array}\}$ ${}^{\prime }{0}^{\prime }$ could not be $1^{st}$ digit but could be $2^{nd}$ digit

Sum $=120+96+96=312$.