Wrong answer 2.1

[mantasu]

If we have 2 actions and $\varepsilon=0.5$, the probability of selecting the greedy action is $0.5 + 0.25=0.75$. We add $0.25$ because we may select a random action with $\varepsilon=0.5$ which can be the greedy action itself. Since there are 2 actions, the "random" probability will be distributed equally $\frac{0.5}{2}=0.25$.

[AbhiDu96]

Correct me if my following reasoning is wrong, but I would like to elaborate on your answer.
With probability 0.5 you select a greedy action and with probability 0.5 you select an action at random from the set {greed, non-greedy}. Thus the probability of selecting a greedy action becomes:
0.5 (from selecting greedy action) + 0.5*0.5 (probability of choosing from the set * probability to choose a greedy action from the set) = 0.75
We add the two probabilities because the two events are exclusive.