Lingua Translations Company wants to determine how many part-time Hungarian translators it should hire. The number of orders per day for Hungarian translations follows a Poisson distribution with an expected value of 8. Each translator can take one order a day. Lingua pays a fixed amount of $10 per day to each translator, whether or not the translator has to fill an order. Furthermore, a translator gets $50 for translating an order. If the company receives more orders than it has translators, it asks the translators whether they are available for overtime. For each translator, the chance of being available for overtime is 40%, in which case the translator can process one additional order. Lingua pays $75 for overtime translation of an order. The company charges its customers $90 per translation order.

In order to maximize its average daily profits, how many translators should Lingua keep on staff?