Question

The sum of the digits of a two-digit number is 7. If the digits are reverses, the new number is 9 more than the original number. Find the original number. ​

Answer 1

25

Explanation

Let the ones's digit =x.

So, sum of the digits =7

Tens's digit =7−x

Original no. =10(7−x)+x=70−10x+x=70−9x

Reversed no. =10x+7−x=9x+7

2(orig no) = reversed no. −2

2(70−9x)=9x+7−2

140−18x=9x+5

27x=135

x=5

Ten's digit =7−5=2

No. =25