Product cost markup percentage 

Magna Lighting Inc. produces and sells lighting fixtures. An entry light has a total cost of $125 per unit, of which $80 is product cost and $45 is selling and administrative expenses. In addition, the total cost of $125 is made up of $90 variable cost and $35 fixed cost. The desired profit is $55 per unit.

How do I Determine the markup percentage on product cost?