Question

In a two digit number unit's digit is 3 more than the ten's digit. The number formed by interchanging the digits and original number the digits and the original number are in the ratio 7 : 4. Find the number .

• A. $63$
• B. $36$
• C. $54$
• D. $45$

Answer 1

Answer: (B)

$36$

$10$'s digit	$1$'s digit
$x$	$x+3$

The number = $10x+x+3=11x+3$
Interchanging the digits

$10$'sdigit	$1$'s digit
$x+3$	$x$

Then the number $=10x+30+x=11x+30$
so $\frac{11x+30}{11x+3}=\frac{7}{4}$
$44x+120=77x+21$
$33x=99$
$x=3$
$\therefore$ The number $=36$