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प्रश्न
If 31z5 is a multiple of 9, where z is a digit, what is the value of z? You will find that there are two answers for the last problem. Why is this so?
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उत्तर
If a number is a multiple of 9, then the sum of its digits will be divisible by 9.
Sum of digits of 31z5 = 3 + 1 + z + 5 = 9 + z
Hence, 9 + z should be a multiple of 9.
This is possible when 9 + z is any one of these numbers 0, 9, 18, 27, and so on …
However, since z is a single digit number, this sum can be either 9 or 18. Therefore, z should be either 0 or 9.
संबंधित प्रश्न
Find the remainder when 51439786 is divided by 3. Do this without performing actual division.
Which of the following statement is true?
If a number is divisible by 3, it must be divisible by 9.
Which of the following statement is true?
If a number is divisible by 9, it must be divisible by 3.
7×34 divisible by 9?
5 × 555 a multiple of 9?
If a number is divisible by 6, then it must be divisible by 3
3134673 is divisible by 3 and ______.
Write the smallest digit and the greatest digit in the blank space of the following number so that the number formed is divisible by 3:
______ 6724
The digit sum of 91 is 10. Therefore, 91 is:
Among 63, 872, and 552, how many numbers are divisible by 3?
