There are thirty games in the season because 20 + 10 = <<20+10=30>>30
He needs to get 90 hits on the year to average 3 hits a game because 30 x 3 = <<90=90>>90
He has 40 hits already because 20 x 2 = <<20*2=40>>40
He needs 50 hits in the final 10 games because 90 - 40 = <<90-40=50>>50
He needs to average 5 hits a game because 50 / 10 = <<50/10=5>>5
#### 5