5.34 A furniture manufacturer has found that the time spent by workers assembling a particular table follows a normal distribution with a mean of 150 minutes and a standard deviation of 40 minutes.

a. The probability is 0.9 that a randomly chosen table requires more than how many minutes to assemble?

b. The probability is 0.8 that a randomly chosen table can be assembled in fewer than how many minutes?

c. Two tables are chosen at random. What is the probability that at least one of them requires at least 2 hours to assemble?