I am sad and that makes me sadder

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64

The weekly amount spent by a company for travel has an approximately normal distribution with mean = $550 and standard deviation = $40. a) what is the probability that the actual weekly expense will exceed $570 for more than 20 weeks during the next year? (note: one year = 52 weeks) b) what is the probability that actual weekly expenses exceed $580 for 10 or more, but 16 or fewer weeks during the next year?

4. jake needs to score in the top 10% in order to earn a physical fitness certificate. the class mean is 78 and the standard deviation is 5.5. what raw score does he need? z value for top 10% =1.282 how do i get the z value? what is the equation for this? raw score =mean+z*sd = 78+1.282*5.5 = 85.051