Question

If 7x8 is exactly divisible by 9, then the least value of x is

• A. 0
• B. 2
• C. 3
• D. 5

Answer 1

The correct option is C

3

7x8 is exactly divisible by 9

$\therefore$ Sum of its digits must be divisible by 9

$\Rightarrow$ 7 + x + 8 = 15 + x must be divisible by 9

15 + x = 9 , 18 , 27 , 36 ...........( Multiples of 9 )

If 15 + x = 9 ; x = - 7

If 15 + x = 18 ; x = 3

If 15 + x = 27 ; x = 12

x cannot take a negative value and double digit number.

Hence least possible value of x = 3