If the number 678967# is exactly divisible by 72, the minimum value o...
Given:
The number 678967# is exactly divisible by 72
Concept used:
If the number is divisible by 72 that means it has to be divisible by 8 and 9 as these are the two factors of 72.
Divisibility rules of 8 : when the number made by last three digits of a number is divisible by 8 then the number is also divisible by 8. Apart from this if the last 3 or more digits of a number are zero then the number is divisible by 8.
Divisibility rules of 9 : when the sum of all the digits of a number is divisible by 9 then the number is also divisible by 9.
Calculations:
The number is 678967#, so if we apply the divisibility rules of 8, the last 3 digits have to be divisible by 8.
Now, 67# has to be divisible by 8, so if we put 2 in place # it becomes 672 which is divisible by 8.
Again, applying divisibility rules of 9, by adding all the numbers = 6 + 7 + 8 + 9 + 6 + 7 + # = 43 + #
So, if we take 2 again in place of # the sum of the numbers become = 45 which is divisible by 9.
Thus, two rules satisfies the condition and the number is 2.
∴ The answer is 2.