Atennis supply store pays a wholesaler $90 for a tennis racquet and sells it for $144. what is the markup rate?

Formula : Amount of change / Original amount

             1.      144 - 90/ 144

             2.      Subtract 144 and 90

             3.      54/ 144

             4.      Divide 54 by 144

             5       0.375

             6       Move the decimal two places to the right.

              7.      37.5 %

37.5% is the markup rate