How is 20/10 trun in to a mixed fraction

Find x to the nearest hundredth place

Find the perimeter of the triangle with vertices  d(3, 4),  e(8, 7), and  f(5, 9). do not round before calculating the perimeter. after calculating the perimeter, round your answer to the nearest tenth.  

1. if events a and b are non-overlapping events, how do you find the probability that one or the other occurs? 2. what does it mean if p(a or b) equals 1?