jmc

For each friend, there are 2 choices for which class to place them in. Since this choice is independent for each of the 6 friends, we multiply the number of choices together. Hence there are $2^6=64$ ways to split the friends into two classes. However, 2 of those 64 arrangements are invalid: we can't put Manoj in chemistry and everyone else in biology, and we can't put Manoj in biology and everyone else in chemistry. So our final answer is $64-2=\boxed{62}$.