Question

The generalised from of the number 95,001 is
loooo x 9 + 1000 X 5 +0+0+1 X1​

Answer 1

Explanation:

Let the original number be 10a + b. 

Then, ‘a’ is the tens digit and ‘b’ is the units digit. 

Since the sum of the digits is 7, 

Therefore a + b = 7, 

i.e., b = 7 - a.. 

So, the original number is 10a + (7 - a). 

Therefore, the number obtained by interchanging the digits is 

10(7 - a) + a, 

and so we have {10(7 - a) + a} — {10a + (7 - a)} = 27. 

Solving this equation, we get 

a = 2. 

And so, b = 7 - 2

= 7 - 2

= 5. 

Hence, the original number is 10a + b = 20 + 5 = 25.