The mark up rate is the percentage that the retailer added to the cost to set the selling price.
Here the amount added to the cost was: $2,259 - $1,659 = $ 600.
The percentage is calculated dividing the amount added to the cost by the same cost and multiplying the result times 100.
($600 / $1,659 ) * 100 = 36.17%
Answer: 36.17%