I'm not very good with stats, the question is for a stats course at Uni, I've posted the question below, what I want to find out is the probability of the chance of the first 2 employees being affected by the bonus, I know that the chance of being affected for the other 2 are 50% as is it equiprobable. I'm not sure how to get the probability for the first two employees. I would be grateful if somebody could explain.
The owner of a small firm is thinking of giving a raise to his four best performing employees to ensure that they will not leave for another company. He knows that some of them are less likely to be affected by the bonus than others so he tries to figure out whether the overall impact is worthwhile. After reviewing the records of the four employees he concluded that one of them is unlikely to be affected to search for another job so he assumes that the chance of being affected by the raise is 70% lower than the chance of not being affected. For another employee he assumes the opposite; and for the other two he assumes that the chances are equiprobable. If his decision to go ahead with his plan depended on whether the probability of the event ‘at least 3 employees will be affected by the raise’ is greater than a threshold value, which of the following options is closer to that probability?