Marta is planning a field trip to the zoo. Admission to the zoo is $12 per student and $20 per adult. What expression represents the total cost of admission for a group of x students and y adults? StartFraction x over 20 EndFraction StartFraction y over 12 EndFraction StartFraction x over 12 EndFraction StartFraction y over 20 EndFraction 12 x 20 y 20 x 12 y.
