Carlos purchased an antique chair for $15 he later so this year for $27 to an antique dealer what was the percent markup of the chair

Okay. So, to find the percent change, we have to do change/original. In this case, it would be 12/15, because 15 and 27 are apart by 12. 12/15 is 0.8. Multiply that by 100 and you get 80. There was an 80% markup of the chair sold to the antique dealer.