25
Step-by-step 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
