out of 0,1,2,3,4,5 six digits, 5 digit multiple of 3 is to be formed.
case 1: when using only 1,2,3,4,5 as the sum is divisible by 3 can be arranged among themselves in !5=120 ways
case2: if we add 0 to the above group then we must remove 3 so as to be multiple of 3.
0 can only be used at units, tens, hundreds and thousands place--4 ways
and rest can be arranged at the leftover 4 places in !4 ways=24
total=24*4=96
hence total no. of requisite such numbers=120+96=216