Question

Ten's digit of a two digits number is greater by 7 than the unit's digit. Sum of the digits is 1/9 of that number. Find the number.

Answer 1

Let No. is 10x+y.

Given,

X=Y+7

X+Y=1/9(10X+Y)

Solving both equation.

we get,

X=8

Y=1

No. will be 81.