Question

3. The sum of the digits of a two digit number is 10.The number formed by interchanging the digits is 36 less than the original number. Find the original number?

How to do this using one variable(only 'x')?
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Answer 1

Answer:

original number = 37

Step-by-step explanation:

let the once digit = x

then the tens digit = 10 - x

then original number is formed = 10× (10 - x) + x

10 × (10 - x) + x = 10 × x + (10 - x) - 36

100 - 10x + x = 10x + 10 - x - 36

100 - 9x = 9x - 26

100 + 26 = 9x + 9x

126 = 18x

126/18 = x

x = 7

so , once digit = x = 7

and , tens digit = 10 - x = 10 - 7

= 3

original number = 10 × (10 - x) + x

10 × 3 + 7

= 37