Question

Which is correct?
1. You definitely helped me to conclude that majoring in both Finance and Accounting IS the right thing to do.
2. You definitely helped me to conclude that majoring in both Finance and Accounting ARE the right thing to do.

Answer 1

#2, because since you are grouping Finance and Accounting together with "and" instead of "or", that means there is more than one subject. So you use ARE to refer to both of them.