You can put this solution on YOUR website! Let X be the number of years.
Three years ago.
When the man was 50, his son was 5 (10x his age).
No solution.
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If you check all of the answers, none of them work.
Example:
A) In 3 years, the man will be 56, the son will be 11. 56 does not equal 110.
Etc.