Question

In a 2-digit number, sum of digits is 7. If the difference of 2 digit number and number obtained by reversing the digits is -9

, then find number.

Answer 1

Let the units digit be x and tens digit be y

then,

$x+y=7...\left(i\right)$

Original number $\Rightarrow 10y+x$

Reversed number $\Rightarrow 10x+y$

$A.t.Q:-(10y+x)-(10x+y)=-9$

$9y-9x=-9$

$-x+y=-1...\left(ii\right)$

By solving (i) & (ii)

$x=4,y=3$

Number: 34