There are 8 weeks and 18 books. therefore you would multiply these numbers together. 
the answer would be 144 different combinations.
not sure about the permutation or combination notation, but I got you on the first part!
        
             
        
        
        
The answer is C. 2.8!!!!!!!!
        
             
        
        
        
Angles in a parallelogram have to equal 360.
Let x represent the measurement of the unknown angle.
2(55) + 2x = 360
110 + 2x = 360
2x = 250
x = 125
125 degrees
        
             
        
        
        
Answer: 4311/9900 = 0.4354 4936/990 = 4.985 530/900 = 0.58 674/990 = 0.680 8099/990 = 8.180 explanation: divide the numbers and select the answers.