Apopulation consists of 200 elements. we want to draw a simple random sample of 40 elements from this population. on the first selection, the probability of an element being selected is

The way to calculate probability is

Probability (event) = number of outcome favorable to event / total number of possible outcome

So we substitute the numbers in
P (an element selected) = 40/200
Now simplify the fraction.
Answer = 1/5

No a triangle cannot be formed because when you add the two smallest number together (which would be 11) the have to be bigger than the number it is "against" ( which would be 12)