Jonah spent 6 x $3 = $<<6*3=18>>18
He made a total of 6 x 12 = <<6*12=72>>72 pineapple rings.
He sold 72/4 = <<72/4=18>>18 sets of pineapple rings.
He made 18 x $5 = $<<18*5=90>>90
His profit was $90 - $18 = $<<90-18=72>>72
#### 72