You can
put this solution on YOUR website!average game he makes 9 out of 21.
His make percentage is 9/21 = .428571429 * 100% = 42.8571429%
He took 357 shots for the month of November.
Assuming he hits the average in all the games, then he hits .428571429 * 357 = 153 and he misses 357 - 153 = 204
This means he misses 204/357 = .571428571 * 100% = 57.1428571% of the time.