Question 551147
The sum of the digits of a certain two digit number is eight. If the original number is subtracted from the number formed by interchanging the digits, the result is -18. What is the original number?
**
let t=ten's digit
let u=unit's digit
t+u=8, t=8-u
original no.=10t+u
interchanged no.=10u+t
..
10u+t-(10t+u)=-18
10u+t-10t-u=-18
10u+8-u-10(8-u)-u=-18
10u+8-u-80+10u-u=-18
18u=54
u=3
t=8-u=5
original number=53