Question

A shelf has 20 bags of potatoes. Two of the bags have potatoes starting to go bad. What is the expected probability of the complement of the event "bad bags of potatoes"?

A.) 0.1

B.) 0.2

C.) 0.8

D.) 0.9

Answer 1

 There are 2 bad bags out of 20, so the probability of bad bags is: 
 $\frac{2}{20} = \frac{1}{10} = 0.1$

But we want the complement, which is the probability of bags which are not bad, and that is :

$1-0.1=0.9$
 

Answer 2

D.) 0.9

A complement of an event is the opposite of what is happening. There are 2 bags out of 20 that are going bad. The complement would be 18 bags out of 20 because those are the amount of bags that are NOT going bad. 

18/20= 9/10= 0.9 

Complement just means opposite.