Answer:
Markup 66.6666666......% = 66 2/3 % (66 and 2/3 percent)
Explanation:
The difference in prices is $150-$90=$60. So, we need to find what percentage of 90 is 60. We do this by dividing: 60/90=0.6666...., which is 66.666...%. So, the markup is 66.666...%. = 66 2/3 %