Does b ! ^ k divide -LRB- b * k -RRB- ! if b , k are positive integers ?
How can you show that -LSB- math -RSB- -LRB- kn -RRB- ! -LSB- / math -RSB- is divisible by -LSB- math -RSB- -LRB- n ! -RRB- ^ k -LSB- / math -RSB- ?