Assume that a fund manager has no idea of hat he is doing and is essentially flipping a coin in order to make decisions. Let's say it's a 50/50 proposition that the manager will have a "good" year. What is the probability that the fund manager will have 6 or more good years out of 10?
Is it (1/2)^6?
Hint: The probability you are looking for is $$ \sum_{k=6}^{10} \binom{10}{k} \left(\frac{1}{2}\right)^k \left(\frac{1}{2}\right)^{10-k}. $$
Left for the reader to simplify the above further.
As @lulu said, read on https://en.wikipedia.org/wiki/Binomial_distribution to arrive at the above answer.