The answer is Ms Hernandez can bring up to 6 people to the zoo.
x - the number of people that she can bring to the zoo
The parking will cost $7: a = 7
Admission tickets will cost $15.50 per person: b = 15.50x
She can spend on parking and admission tickets $100:
a + b ≤ 100
a = 7
b = 15.50x
7 + 15.50x ≤ 100
15.50x ≤ 100 - 7
15.50x ≤ 93
x ≤ 93 / 15.50
x ≤ 6
