Ellen and Lenny have some sweets.  If Ellen gives away $12$ sweets, the number of sweets Ellen has is $\frac{13}{24}$ of the total number of sweets that both have. If Lenny gives away $12$ sweets, the number of sweets Lenny has is $\frac{3}{8}$ of the total number of sweets that both have. How many sweets do they have altogether? 
Overseas Competition->Knowledge Point->Calculation Modules->Fractions