Answer:
Vertical angles are always equal to one another. In general, we can say that, 2 pairs of vertical angles are formed when two lines intersect.
Step-by-step explanation:
Parallel lines are lines that do not meet at any point in a plane.
Intersecting lines are straight lines that meet or crosses each other at a certain point.
 
        
             
        
        
        
Answer:A
Step-by-step explanation:
 
        
             
        
        
        
18 choose 7 
=C(18,7)
=18!/(7!(18-7)!)
=31824
OR
18 choices for first passenger,
17 choices for second passenger,
....
12 choices for 7th passenger,
so total = 18*17*16...12
but there are 7! ways to order the 7 passengers, so
number of groups
=18*17*16...12/7!
=31824   as well
        
             
        
        
        
Answer:
<h3>r =-12</h3>
Step-by-step explanation:
