A number consists of two digits whose sum is 8 if 18 is added to the number its digits are reversed find the number.

Explanation

Unit digit be =` x`
Ten digit =`8-x`
Original number
`10(8-x)+x`
`80-10x+x`
`80-9x`
Reversed number
`10x+8-x`
`9x+8`
According to question
`80-9x+18=9x+8`
`9x+9x=80+18-8`
`18x=90`
`x=90/18`
`x=5`
Original number
`80=9xx5`
`80-45`
`35`