Question 950162: the sum of the digits of a certain two-digit number is 7 reversing the digits increases the number by 9. what is the number Answer by lwsshak3(11628) (Show Source):
You can put this solution on YOUR website! the sum of the digits of a certain two-digit number is 7 reversing the digits increases the number by 9. what is the number
***
let u=units digit
let t=tens digit
u+t=7
t=7-u
..
number=10t+u
reversing digits number=10u+t
..
10u+t-(10t+u)=9
10u+t-10t-u=9
10u+(7-u)-10(7-u)-u=9
10u+7-u-70+10u-u=9
18u=72
u=4
t=7-u=3
number: 10t +u=30+4=34
(