Johnny bought 15 packs, and every normal pack has 1 red pencil. He should have 15 * 1 = <<15*1=15>>15 red pencils.
3 of the packs have 2 extra red colored pencils, so there are 3 * 2 = <<3*2=6>>6 extra red pencils.
In total, Johnny has 15 + 6 = <<15+6=21>>21 red colored pencils.
#### 21