Question 1117309
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If you need an algebraic solution, the one from the other tutor is fine.  And it is good to know how to solve problems like this using algebra.<br>
But if you just need to solve the problem, logical analysis is much faster.<br>
The man is 36 and his sister is 29; the difference in their ages is 7.
So when the man was twice as old as his sister, she was 7 and he was 14.
Since the man is now 36, that was 22 years ago.