Answer:
Solution,
Let the age of sister be X
Let the age of boy be 2x
Now,
Five years ago,
[tex]3(x - 5) = 2x - 5 \\ or \: 3x - 15 = 2x - 5 \\ or \: 3x - 2x = - 5 + 15 \\ x = 10[/tex]
Again,
Replacing value,
[tex]age \: of \: boy = 2x \\ \: \: \: \: \: \: \: \: \: \: \: \: \: = 2 \times 10 \\ \: \: \: \: \: \: \: \: \: \: \: = 20[/tex]
hope this helps..
Good luck on your assignment..