Question

Question 19

In the given question, fill in the blanks to make the statement true.

20x3 is a multiple of 3, if the digit x is ___ or ___ or ___.

Answer 1

1, 4, 7
We know that, if a number is a multiple of 3, then the sum of its digits is again a multiple of 3, i.e. 2 + 0 + x + 3 is a multiple of 3.
$\Rightarrow$ x + 5 = 0, 3, 6, 9, 12, 15
But, x is a digit of the number 20x3.
$\therefore$ x can take values 0, 1, 2, 3,.....9.
$\Rightarrow$ x + 5 = 6 or 9 or 12
Hence, x = 1 or 4 or 7