A certain typing agency employs two typists. The average number of errors per article is XXXXXXXXXXwhen typed by the first typist and 55 when typed by the second. If your article is equally likely to...

A certain typing agency employs two typists. The average number of errors per article is 1.21.2 when typed by the first typist and 55 when typed by the second. If your article is equally likely to be typed by either typist, find the probability that it will have no errors.