The jurassic zoo charges $13 for each adult admission and $5 for each child. the total bill for the 152 people from a school trip was $1096 . how many adults and how many children went to the zoo?   

c - number of children
a - number of adults

c+a=152

13a - was paid for adult's tickets
5c - was paid for child's tickets

13a+5c = 1096

13a+5c = 1096
(a+c=152) * -13 > -13a - 13c = -15213 >-13a - 13c = -15213=-1976

13a+5c = 1096
-13a - 13c=-1976

8c =-880
c=110
c+a=152
110+a=152
a=42

Check:

1342+5110 = 1096
1096=1096 True

lockers 1, 4, 9, 16, 25, 40, and 49 are open

i ran through it by the other answer is wrong