Question 40522
The percent markup would be 
[(selling price) - (cost to make) / (cost to make)] x 100
{{{(150x - (90x - .02x^2)) / (90x - .02x^2)}}} =
{{{(150x / (90x - .02x^2)) - 1}}} =
{{{(150 / (90 - .02x)) - 1}}} 
find percent markup for x = 60
{{{(150 / (90 - 1.2)) - 1}}} = 
{{{(150/88.8) - 1}}}
{{{1.689 - 1}}} = .689
percent markup is 100 x .689, or about 69%