Each flipping is independent, and the probability of getting a head per flipping is 1/2, so the probability of getting 11 heads in a row is (1/2)^11=1/2048.
Interpret (not sure what your instructor wants, but this is how I would interpret it): when a coin is flipped 11 times, there are 2048 outcomes, only one of the outcomes is 11 heads in a row.
For this one it's really simple. Just do 90-(-2). It may look confusing right now, but it's really easy. All you need to know is that a negative and a negative cancel out to form a positive. So it's actually 90+2. 92 is the difference.
