Find the lowest positive value of (c – b) such that the 7-digit number 1738b9c is divisible by 12.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 2.
For a number to be divisible by 12, it must be divisible by both 3 and 4
Divisibility rule of 3:- For a number to be divisible by 3, the sum of its digits must be divisible by 3
Divisibility rule of 4:- For a number to be divisible by 4, the last 2 digits must be divisible by 4
The sum of the given number = 28 + b + c
c can take values = 2 or 6
Now this sum needs to be divisible by 3
This can happen when b = 0 and c = 2
Hence, the lowest possible value of c - b = 2