Mr Smith is a local tax agent with 20 years of experience. He knows that the time taken to complete a single tax return is normally distributed with a mean of 30 minutes and a standard deviation of 12 minutes. i) ii) Find the probability that a selected tax return will take more than 50 minutes to complete Mr. Smith has just been approached by a small company for him to complete the tax returns of all of their 20 employees within the next working day. Assuming that Mr. Smith works 8 hours a day, what is the probability that the total time it takes Mr. Smith to complete all the tax returns for the 20 employees is less than 8 hours?