Jenna bought two more pairs of jeans. if both of them are blue, what percentage of her jeans is blue now? if both of them are not blue, what percentage of her jeans is blue now? blue=50% if they are not blue=__ me

What you must keep in mind is that there are 4 jeans in total, which represents 100%
 When she bought two jeans, we have the following information:
 If both of them are blue:
 50% of their jeans is blue now, that is:
 x = (50/100) * 4 = 2
 2 jeans are blue.
 This means that she did NOT have 2 blue jeans before.
 Thus:
 If they are not blue: 
 We have 4 jeans that are not blue.
 Then, 0% of her jeans is blue now
 
 0% percentage of her jeans is blue now