When a certain type of thumbtack is tossed, the probability that it lands tip up is 20%, and the probability that it lands tip is 80%. All possible outcomes when two thumbtacks are tossed are listed. U means the tip is up and D means the tip is down.

All possible outcomes when two thumbtacks are tossed are listed

{ UU ,UD,DU,DD} here U means the tip is up and D means the tip is down.

The probabilities of all these possible outcomes are

{ p(UU) ,p(UD),p(DU),p(DD)} are {1/25 , 4/25 ,4/25 , 16/25}

Step-by-step explanation:

The probability that it lands tip up is 20% P(U) =  

The probability that it lands tip up is 80% P(D) =  

All possible outcomes when two thumbtacks are tossed are listed

{ UU ,UD,DU,DD} here U means the tip is up and D means the tip is down.

note:- The sum of all probabilities is equal to one

that is =

the answer would be 150 books

step-by-step explanation:

if you divide 300 by 2 you will get 150