Jon decides to take up baseball.  He can throw a fastball at 80 miles per hour.   He goes through intense training 4 times for 4 weeks each time and at the end of the last one he can throw a ball 20% faster.  How much speed (in mph) did he gain per week, assuming he gained an equal amount of speed (in mph) each week?
He threw the ball 80*.2=<<80*.2=16>>16 mph faster
He was training for 4*4=<<4*4=16>>16 weeks
So he gained 16/16= <<16/16=1>>1 mph per week
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