Denote the number by
, where
are positive integers between 0 and 9
.
"the tens digit is two less than the units digit"
![\implies a=b-2](https://img.qammunity.org/2020/formulas/mathematics/high-school/25c28134my5nacx7jq6o6m3hj0paijsu7y.png)
Reversing digits gives a new number
.
"sum of the reversed number and the original number is 154"
![\implies10(a+b)+(b+a)=154](https://img.qammunity.org/2020/formulas/mathematics/high-school/l12b6wdjueh9pwi2wa4qgk9fk3c3jtnux0.png)
Simplify the second equation:
![11(a+b)=154\implies a+b=(154)/(11)=14](https://img.qammunity.org/2020/formulas/mathematics/high-school/dncikjj4ewgxei6ip40rou2l6uw76xx19k.png)
Since
, by substitution we get
![(b-2)+b=2b-2=2(b-1)=14\implies b-1=\frac{14}2=7\implies b=8](https://img.qammunity.org/2020/formulas/mathematics/high-school/dv9gjxerrs16rs1qik21f95tnw4qfvb06h.png)
which in turn gives
![a=8-2=6](https://img.qammunity.org/2020/formulas/mathematics/high-school/h077s9g0ohkrrevm4fzx8u8d4i0kbe7iu0.png)
So the original number is
.