Question 658775
The sum of the digits of a two digit number is 9. Also, nine times this number is twice the number obtained by reversing the digits of the number. Find the number.
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let u=units digit
let t=tens digit
t+u=9
t=9-u
number=10t+u
..
9(10t+u)=2(10u+t)
90t+9u=20u+2t
11u=88t=88(9-u)=792-88u
99u=792
u=792/99
u=8
t=9-u=1
10t+u=10+8=18
number=18