Every student in the senior class is taking history or science. there are $200$ seniors in the class. if there are $126$ seniors taking history and $129$ seniors taking science, how many students are taking both history and science?

Darcy deposited $390 into a savings account. as long as the account balance remains at or above $150, she does not have to pay a service fee for the account. for how many months can she withdraw $40 a month without having to pay service fees? a) 3 b) 5 c) 6 d) 9