Question

If a $3$ digit numbers $4a3$ is added to another $3$ digit number $984$ to give four digit number $13b7$ and it is visible by $11,$ then $a+b=?$

• A. $9$
• B. $11$
• C. $10$
• D. $12$

Answer 1

The correct option is C $10$

Given,

$4a3+984=13b7$

solving the above equations separately, we get,

$a+8=b$

$b-a=8$

Also, $13b7$ be divisible by $11$

as per the rule for the number to be divisible by $11$, we have,

$(7+9)-(1+b)=9-b$

$9-b=0$

$\therefore b=9$

$\Rightarrow a=1$

$\therefore a+b=10$