If x is a digit such that the number is divisible by 3, find possible values of x.
Here it is given that is divisible by 3.
We know that if a number is divisible by 3, then sum of digits must be a multiple of 3.
∴ 1 + 8+x+7+1 = multiple of 3
∴ a + 17 = 0,3,6,9,12,15,…..
But ‘x’ is a digit, hence, ‘x’ can have value between 0 to 9.
∴ x + 17 = 18 which gives x = 1.
∴ x+ 17 = 21 which gives x = 4.
∴ x + 17 = 24 which gives x = 7.
∴ x = 1,4,7