A three-digit number 42x is divisible by 9. Find the value of x.
Solution:
A number is divisible by 9 if the sum of its digits is 9 or any number divisible by 9.
So if the number 42x has to be divisible by 9 then 4 + 2 + x = 9 or any number divisible by 9.
Hence x = 9 - 6 = 3. Therefore the number will be 423.
The next number divisible by 9 is 18. Therefore
4 + 2 + x = 18
x = 18 - 6 = 12
The digit x cannor be two digit hence the three digit number divisible by 9 will be 423.
✦ Try This: A three digit number 1x3 is divisible by 11. Find the value of x.
For a number to be divisible by 11 the condition is that the difference of the sum of alternative digits is either zero or is divisible by 11.
x - (1 + 3) = 0
x = 4
Alternatively
x - (1 + 3) = 11
x = 11 + 4 = 15
But x cannot be two digits. Hence,
The three digit divisible by 11 is 143.
☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 16
NCERT Exemplar Class 8 Maths Chapter 13 Sample Problem 11
A three-digit number 42x is divisible by 9. Find the value of x.
Summary:
A three-digit number 42x is divisible by 9. The value of x is 3.
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