Graziano predicted that he would sell 420 tablecloths. He actually sold 520 tablecloths. What are the values of a and b in the table below? Round the answer to the nearest tenth. Percent ErrorItemApproximate valueExact valueErrorAbsolute errorRatioPercent errorTablecloths420520aba = Negative StartFraction 100 over 420 EndFraction; b = negative 23.8 percenta = Negative StartFraction 100 over 520 EndFraction; b = negative 19.2 percenta = StartFraction 100 over 520 EndFraction; b = 19.2 percenta = StartFraction 100 over 420 EndFraction; b = 23.8 percent