A certain zoo charges exactly twice as much for an adult admission

A certain zoo charges exactly twice as much for an adult admission ticket as for a childs admission ticket. If the total admission price for the family of two adults and two children is $12.60, what is the price of a childs ticket? (A) $1.60 (B) $2.10 (C) $3.20 (D) $3.30 (E) $4.20 Source: (…)