[3.1 x 10^5] / 40 words per minute =7,750 minutes
1 hour = 60 minutes.
7,750 /60 = 129 1/6 - hours to type 3.1 x 10^5 words.
OR:
40 words per minute x 60 minutes =2,400 words - that he can type in 1 hour
[3.1 x 10^5] / 2,400 words per/h =129 1/6 hours to type 3.1 x 10^5 words.
