His total without the coupons was $20 - $5.50 = $<<20-5.5=14.50>>14.50
He had 5 coupons that each saved him 25 cents, so the full price of all the tuna is $14.50 + 5*$0.25 =$15.75.
He bought 9 cans of tuna, so each can costs $15.75 / 9 = $<<15.75/9=1.75>>1.75
As 1 dollar has 100 cents 1.75 * 100 = <<1.75*100=175>>175 cents
#### 175