Working together, it takes two computers 20 minutes to send out a company's email. if it takes the slower computer 45 minutes to do the job on its own, how long will it take the faster computer to do the job on its own?

This is a map of the mars exploration rover opportunity predicted landing site on mars. the scale is 1cm : 9.4km. what are the approximate measures of the actual length and width of the ellipse? i mostly need to know how to set it up : )