In $$20$$ years, Li will be $$3$$ times his age now, so $$20$$ must be twice his age now. Thus, Li is $$10$$ now and will be $$20$$ in $$10$$ years. 
In $$20$$ years, Li will be $$3$$ times as old as he is now. How old will he be in $$10$$ years? 
Options:
a. $$10$$ 
b. $$20$$ 
c. $$30$$ 
d. $$50$$ 