Question 564704
five times the sum of the digits of a two digit number equals the number. if the digits are reversed, it becomes nine more than the original number. what is the original number?
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let u=units digit
let t=tens digit
..
original number: 10t+u
5(u+t)=10t+u
10u+t=9+10t+u
..
From first equation:
5u+5t=10t+u
4u=5t
u=5t/4
..
From second equation:
9u-9t=9
9(u-t)=9
u-t=1
5t/4-t=1
t/4=1
t=4
u=t+1=5
ans:
original number=45