Show work

12 pts The amount of time it takes John Johnson, a motivational speaker, to make his presentation is distributed continuously and uniformly between 40 and 60 minutes. Members of the University of Washington's statistics club have invited John to give his presentation. (WORK REQUIRED for EACH part). a) What is the standard deviation of the amount of time, in minutes, John's presentation will last? (SHOW WORK; 4 points) b) What is the value, in minutes, at the 65th percentile of the associated distribution? (SHOW WORK; 8 points)