How many positive multiples of 3 less than 1000 use only the digits 2 and/or 4 and/or 6?
+526 I'm assuming repetition of digits are allowed.
No. of 1-digit no.'s = 1 (6)
No. of 2-digit no.'s = 3 (24,42 & 66)
No. of 3-digit no.'s = 9 (222,246,264,444,426,462,666,624 & 642)
So total no. of multiples = 1+3+9
= 13
